GLASILO SLOVENSKIH TEKSTILCEV • SLOVENE JOURNAL FOR TEXTILE AND CLOTHING TECHNOLOGY, DESIGN AND MARKETING tekstilec 3/2020 • vol. 63 • 163-238 ISSN 0351-3386 (tiskano/printed) ISSN 2350 - 3696 (elektronsko/onllne) UDK677 + 687 (05) http://www.tekstilec.si Časopisni svet/Publishing Council Barbara Simončič, predsednica/President Katja Burger, Univerza v Ljubljani Silvo Hribernik, Univerza v Mariboru Tatjana Kreže, Univerza v Mariboru Gašper Lesjak, Predilnica Litija, d. o. o. Nataša Peršuh, Univerza v Ljubljani Petra Prebil Bašin, Gospodarska zbornica Slovenije Melita Rebič, Odeja, d. o. o. Tatjana Rijavec, Univerza v Ljubljani Daniela Zavec, ZITTS Helena Zidarič Kožar, Inplet pletiva d. o. o. Vera Žlabravec, Predilnica Litija, d. o. o. Glavna in odgovorna urednica/ Editor-in-Chief Tatjana Rijavec Namestnica glavne in odgovorne urednice/Assistant Editor Tatjana Kreže Področni uredniki/Associate Editors Matejka Bizjak, Katja Burger, Andrej Demšar, Alenka Pavko Čuden, Andreja Rudolf, Barbara Simončič, Sonja Šterman, Brigita Tomšič, Zoran Stjepanovic Izvršna urednica za podatkovne baze/ Executive Editor for Databases Irena Sajovic Mednarodni uredniški odbor/ International Editorial Board Arun Aneja, Greenville, US Andrea Ehrmann, Bielefeld, DE Aleš Hladnik, Ljubljana, SI Petra Forte Tavčer, Ljubljana, SI Darinka Fakin, Maribor, SI Jelka Geršak, Maribor, SI Karl Gotlih, Maribor, SI Memon Hafeezullah, Shanghai, CN Abu Naser Md. Ahsanul Haque, Daka, BD Geelong, AU Ilda Kazani, Tirana, AL Svjetlana Janjic, Banja Luka, BA Igor Jordanov, Skopje, MK Petra Komarkova, Liberec, CZ Mirjana Kostic, Beograd, RS Manja Kurečič, Maribor, SI Rimvydas Milasius, Kaunas, LT Olga Paraska, Khmelnytskyi, UA Irena Petrinic, Maribor, SI Željko Penava, Zagreb, HR Tanja Pušic, Zagreb, HR Zenun Skenderi, Zagreb, HR Snežana Stankovic, Beograd, RS Jovan Stepanovic, Leskovac, RS Zoran Stjepanovic, Maribor, SI Simona Strnad, Maribor, SI Jani Toroš, Ljubljana, SI Mariana Ursache, Iai, RO Antoneta Tomljenovic, Zagreb, HR Dušan Trajkovic, Leskovac, RS Hidekazu Yasunaga, Kyoto, JP tekstilec (ISSN: 0351-3386 tiskano, 2350-3696 elektronsko) je znanstvena revija, ki podaja temeljne in aplikativne znanstvene informacije v fizikalni, kemijski in tehnološki znanosti, vezani na tekstilno in oblačilno tehnologijo, oblikovanje in trženje tekstilij in oblačil. V prilogah so v slovenskem jeziku objavljeni strokovni članki in prispevki o novostih v tekstilni tehnologiji iz Slovenije in sveta, prispevki s področja oblikovanja tekstilij in oblačil, informacije o raziskovalnih projektih ipd. tekstilec (ISSN: 0351-3386 printed, 2350-3696 online) the scientific journal gives fundamental and applied scientific information in the physical, chemical and engineering sciences related to the textile and clothing industry, design and marketing. In the appendices written in Slovene language, are published technical and short articles about the textile-technology novelties from Slovenia and the world, articles on textile and clothing design, information about research projects etc. Dosegljivo na svetovnem spletu/Available Online at www.tekstilec.si Crossref Tekstilec je indeksiran v naslednjih bazah/Tekstilec is indexed in Emerging Sources Citation Index - ESCI/Clarivate Analytics SCOPUS/Elsevier (2018: Q3, SJR 0.16, Cite Score 0.45, SNIP 0.612 - v sodelovanju z/in cooperation with Leiden University's Center for Science & Technology Studies) Ei Compendex DOAJ WTI Frankfurt/TEMA® Technology and Management/TOGA® Textile Database World Textiles/EBSCO Information Services Textile Technology Complete/EBSCO Information Services Textile Technology Index/EBSCO Information Services Chemical Abstracts/ACS ULRICHWEB - global serials directory LIBRARY OF THE TECHNICAL UNIVERSITY OF LODZ dLIB SICRIS: 1A3 (Z, A', A1/2) tekstilec Revija Tekstilec izhaja štirikrat letno / Journal Tekstilec appears quarterly Revija je pri Ministrstvu za kulturo vpisana v razvid medijev pod številko 583. Letna naročnina za člane Društev inženirjev in tehnikov tekstilcev je vključena v članarino. Letna naročnina za posameznike 38 € za študente 22 € za mala podjetja 90 € za velika podjetja 180 € za tujino 110 € Cena posamezne številke 10 € Na podlagi Zakona o davku na dodano vrednost sodi revija Tekstilec med proizvode, od katerih se obračunava DDV po stopnji 5 %. Transakcijski račun 01100-6030708186 Bank Account No. SI56 01100-6030708186 Nova Ljubljanska banka d. d., Trg Republike 2, SI-1000 Ljubljana, Slovenija, SWIFT Code: LJBA SI 2X. Ustanovitelja / Founded by • Zveza inženirjev in tehnikov tekstilcev Slovenije / Association of Slovene Textile Engineers and Technicians • Gospodarska zbornica Slovenije - Združenje za tekstilno, oblačilno in usnjarsko predelovalno industrijo / Chamber of Commerce and Industry of Slovenia - Textiles, Clothing and Leather Processing Association Revijo sofinancirajo / Journal is Financially Supported • Univerza v Ljubljani, Naravoslovnotehniška fakulteta / University of Ljubljana, Faculty of Natural Sciences and Engineering • Univerza v Mariboru, Fakulteta za strojništvo / University of Maribor, Faculty for Mechanical Engineering • Javna agencija za raziskovalno dejavnost Republike Slovenije / Slovenian Research Agency Izdajatelj / Publisher Univerza v Ljubljani, Naravoslovnotehniška fakulteta / University of Ljubljana, Faculty of Natural Sciences and Engineering Sponzor/Sponsor Predilnica Litija, d. o. o. Naslov uredništva / Editorial Office Address Uredništvo Tekstilec, Snežniška 5, SI-1000 Ljubljana Tel./Tel.: + 386 1 200 32 00, +386 1 200 32 24 Faks/Fax: + 386 1 200 32 70 E-pošta/E-mail: tekstilec@ntf.uni-lj .si Spletni naslov / Internet page: http://www.tekstilec.si Lektor za slovenščino / Slovenian Language Editor Milojka Mansoor Lektor za angleščino / English Language Editor Tina Kočevar Donkov, Glen David Champaigne Oblikovanje platnice / Design of the Cover Tanja Nuša Kočevar Oblikovanje / Design Miha Golob Oblikovanje spletnih strani / Website Design Jure Ahtik Tisk / Printed by PRIMITUS, d. o. o. Copyright © 2020 by Univerza v Ljubljani, Naravoslovnotehniška fakulteta, Oddelek za tekstilstvo, grafiko in oblikovanje Noben del revije se ne sme reproducirati brez predhodnega pisnega dovoljenja izdajatelja/No part of this publication may be reproduced without the prior written permission of the publisher. I VOLUME 63 • TEKSTILEC 3 2020 ISSN 0351-3386 (tiskano/printed) I6KSIII6C UDK 677 + 687 (05) SCIENTIFIC ARTICLES/ Znanstveni članki 166 Md. Mazharul Islam, Mohammad Abdul Jalil, Md. Shohan Parvez, Md. Mahbubul Haque Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations Ocena dejavnikov, ki vplivajo na natančnost ocenjevanja gradiranja oblačil: prepoznavanje težav in priporočila 185 Sukhvir Singh Development of a Collection of Garments Inspired by the Hawa Mahal Historical Monument Razvoj kolekcije oblačil, navdihnjene z zgodovinskim spomenikom Hawa Mahal 195 Kamrun Nahar, Shurfun Nahar Arju, Jannatul Ferdush, Marzia Islam, Tarifun Akter Colorimetric Analysis and Fastness Properties of Jute Fabric Dyed with Eucalyptus Leaves Kolorimetrična analiza in obstojnost jutne tkanine, barvane z listi evkaliptusa 203 Snježana Kirin, Anica Hursa Šajatovic Determination of Working Methods and Normal Times of Technological Sewing Operation using MTM System Določitev metod dela in časovnih normativov operacij tehnološkega šivanja s sistemom MTM 216 Blaženka Brlobašic Šajatovic, Darko Ujevic, Slavenka Petrak Body Proportions of Football Players and the Untrained Population, and the Impact on the fit of the Trousers Vpliv telesnih proporcev nogometašev in netrenirane populacije na prileganje hlač 225 Timo Grothe, Jan Lukas Storck, Marius Dotter, Andrea Ehrmann Impact of Solid Content in the Electrospinning Solution on the Physical and Chemical Properties of Polyacrylonitrile (PAN) Nanofibrous Mats Vpliv koncentracije elektropredilne raztopine na fizikalne in kemijske lastnostipolikrilonitrilnih (PAN) nanovlaknatih kopren 233 Snezhina Angelova Andonova Influence of Fusing Conditions on the Change of Colour Shade in the Production of Clothing Vpliv pogojev fiksiranja na spremembo barvnega odtenka pri proizvodnji oblačil 166 Tekstilec, 2020, Vol. 63(3), 166-184 | DOI: 10.14502/Tekstilec2020.63.166-184 Md. Mazharul Islam1, Mohammad Abdul Jalil2, Md. Shohan Parvez2, Md. Mahbubul Haque3 1 Northern University Bangladesh (NUB), Department of Textile Engineering, Dhaka, Bangladesh 2 Khulna University of Engineering & Technology, Department of Textile Engineering, Khulna, Bangladesh 3 Daffodil International University, Department of Textile Engineering, Dhaka, Bangladesh Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations Ocena dejavnikov, ki vplivajo na natančnost ocenjevanja gradiranja oblačil: prepoznavanje težav in priporočila Original Scientific Articie/Izvirniznanstveni članek Received/Prispelo 04-2020 • Accepted/Sprejeto 05-2020 Corresponding author/Korespondenčni avtor: Md. Shohan Parvez E-mail: shohan.parvez@te.kuetac.bd ORCID: 0000-0003-3167-2240 Abstract Grading is an inseparable part of producing multiple sized patterns in clothing production. From the inception of apparel manufacturing, various methods have been developed for precision pattern grading. Nevertheless, most conventional grading systems have some flaws. The objectives of this study were to analyse traditional grading systems, identify the factors responsible for pattern grading deficiencies and finally, recommend suggestions to minimise grading problems related to the use of CAD software. For the experiments, three different measurement sheets of different buyers were collected and combined into a single specification for better comparison. All garment patterns were then drawn and graded with varying parameters. Later on, measurements of graded patterns were analysed for grading accuracy. This study presents the factors responsible for grading deficiencies and how they can be minimised for higher precision grading for the better fitting of clothing and the prevention of garment sample rejection before bulk production. Keywords: grading, CAD, pattern making, grading system, grading problems Izvleček Gradiranje je neločljiv del izdelave krojev oblačil različnih velikosti v proizvodnji oblačil. Od začetka industrijske izdelave oblačil so bile razvite različne metode za natančno gradiranje krojev oblačil. Kljub temu pa ima še vedno večina kon-vencionalnih sistemov gradiranja nekaj pomanjkljivosti. Cilji študije so bili analizirati tradicionalne sisteme gradiranja, ugotoviti dejavnike, ki vplivajo na pomanjkljivosti pri gradiranja krojev oblačil, in na koncu izdelati priporočila za zmanjšanje težav pri gradiranju z uporabo programske opreme CAD. Za eksperimente so bile pridobljene tri specifikacije mer različnih kupcev, združene v eno specifikacijo za lažjo primerjavo. Nato so bili konstruirani vsi krojni deli oblačila in gradirani z različnimi parametri. Kasneje so bile analizirane meritve gradiranih krojnih delov glede natančnosti gradiranja. Študija razkriva dejavnike pomanjkljivosti gradiranja in kako jih je mogoče minimalizirati, da dosežemo večjo natančnost gradiranja za boljše prileganje oblačil in preprečevanje zavrnitve oblačila pred masovno izdelavo. Ključne besede: gradiranje, CAD, konstruiranje kroja oblačil, sistem gradiranja, problemi gradiranja Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations 167 1 Introduction Today's business policy for apparel manufacturers requires quick response systems that turn out a wide variety of products to meet customers' demand. In the apparel industry, in particular, stakeholders are trying to develop their current systems for new production techniques in order to keep pace with the rapid changes in the fashion and clothing industry [1]. The garment production process is separated into four main phases: designing and clothing pattern generation, fabric spreading and cutting, sewing and ironing and packing [2]. In order to manufacture apparel, proper sizing information is mandatory. Sizing is the process used to create a size chart of key body measurements for a range of apparel sizes [3]. For the mass production of ready-to-wear clothing, it is necessary to create all sized garments in the size range or sizes provided in the specification sheet. However, the creation of all size patterns is cumbersome and time-consuming. Pattern grading is traditionally used to create various sizes. Grading is a complex process used to create a complete set of patterns of different sizes contained in the size range. This is done by creating a pattern of a selected base size and then grading it up to create the largest sizes and down to create the smallest sizes. To grade a pattern, a set of grade rules are created or grading increment values are calculated. They are then inserted into the grade or cardinal point. Grade points or cardinal points are those points present at the perimeter of the pattern and distribute the changes in body dimension [4]. Generally, pattern grading is done to increase or decrease the dimension of the pattern to reproduce a complete set of patterns of different sizes in the size range to fit a group of people [5-6]. At present, with the mass the customisation of apparel sizing, advanced computer technology is being used widely [7]. Primarily for quick and precise production in apparel manufacturing, flexible computer-aided manufacturing systems are being applied to apparel manufacturing processes, such as apparel pattern making, grading, and marker making [8-9]. Computer-aided pattern making and grading are based on 2D and 3D CAD technologies. Individual patterns created using basic 2D pattern technologies apply grading and alternation rules [10]. In addition to individual patterns created by 3D CAD technology are 2D patterns that are flattened from a 3D body model, so that they reflect the human body type. However they have practical limitations, including the need to build a new 3D CAD system on the top of the existing apparel manufacturing process [11-13]. For that reason, 2D CAD technology is currently used in the apparel industry primarily for mass customisation. Although the 2D CAD system provides time-saving solutions, the latter are not free from limitations. The grade rule creation or grading increment calculation, which is used by all types of 2D apparel CAD to complete the grading process, is based on manual calculation and inputs [14]. Computerised pattern grading is the most precise and expedient method, but only when an accurate value is entered into the computer [6]. Nevertheless, there are many factors that influence grading and lead to grading deficiencies. The objectives of this study were to identify and analyse the reasons behind the inaccuracy and associated problems, while maintaining the required level of precision in garment pattern grading. 2 Methodology 2.1 Materials For experiments, three different specification sheets (hereinafter: spec sheets) of different buyers were collected and then combined and drawn to a solitary sketch of a T-shirt (Figure 1 and Table 1), including all points of measures (POM) for the sake of easy comparison. For example, shoulder point can be calculated using three POMs in combination, if any two of "S", "SD and "AS" are given. Table 1: Measurement points and descriptions of all three specification sheets 2.2 Methods The patterns of T-shirts of specifications A, B and C were drawn and graded with varying parameters. The measurements of graded patterns were then checked for grading accuracy. The conventional grading system is based on the increment of the given measurement of apparel for different sizes using the Cartesian coordinate values of the grading increment. For example, if high point shoulder is increased by 2 cm, points H and G should increase by 2 cm in the direction of Y. For T-shirt Specs A, B and C, cardinal points represented by A, B, C, E, G, H for front and back and A, B, C, D, E, F, G for sleeve and the Cartesian coordinate values of the grading increment as (X, Y) are shown in Figure 2. The body parts of the three specification sheets have the same grading increment value despite differences in measurement location. In case of the sleeve, however, it is 168 Tekstilec, 2020, Vol. 63(3), 166-184 Table 1: Measurement points and descriptions of all three specification sheets Figure 1: Combination of all measurement points of T-shirt Points A M Q Y Description Back neck drop or depth Front neck drop or depth Neck width or opening Across shoulder width or shoulder to shoulder width Shoulder length Shoulder drop or slant Armhole straight Armscye depth Half chest girth High point shoulder Sleeve length Sleeve opening Under sleeve length Sleeve width or upper arm width Sleeve cap height Shoulder slant in degree POMs BND FND NW AS SD AHS ASD HC HPS SL SO US SW SCH SSD POM Reference spec A Reference spec B Reference spec C M XL XXL M XL XXL M XL XXL BND 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 FND 8.5 9.5 10 8.5 9.5 10 8.5 9.5 10 NW 16 17 18 19 20 16 17 18 19 20 16 17 18 19 20 AS 45 48 51 54 57 45 48 51 54 57 15 16 17 18 19 15 16 17 18 19 SD AHS 24 25 26 27 28 24 25 26 27 28 ASD 29 30 31 32 33 HC 48 51 54 57 60 48 51 54 57 60 48 51 54 57 60 HPS 70 72 74 76 78 70 72 74 76 78 70 72 74 76 78 SL 21 22 23 24 25 21 22 23 24 25 21 22 23 24 25 SO 18 19 20 21 22 18 19 20 21 22 18 19 20 21 22 US 14 14.5 15 15.5 16 SW 23 23.75 24.5 25.25 26 23 23.75 24.5 25.25 26 SCH 9.55 10.40 11.25 12.10 12.95 Note: All units are measured in cm. POM: Points of measure B C D E S F G H R S T X S L S L S L 8 9 8 9 8 9 S 5 5 5 5 5 5 5 5 5 5 Figure 2: Cardinal points and Cartesian coordinate values of T-shirt spec A, B, and C Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems identification and Recommendations 169 important to match the sleeve front and back curve with armhole front and back curve. For both Spec A and B, armhole straight is given, which is a diagonal measurement. In the case of Spec C, however, there are no diagonal measurements. Thus, the impact of the diagonal measurement is explained further in the following sections "presence of diagonal measurement" and "maintaining accuracy and matching of curve line". 2.2.1 Presence of diagonal measurements Some inclined or diagonal POMs (points of measure) create measurement errors in the traditional XY Cartesian coordinate apparel pattern grading system. In every grading textbook, different authors mention different types of shoulder seam grading [6, 15-18]. There is no consistency on how the textbook authors grade the shoulder [19]. For shoulder seam grading in the conventional method, some assumptions have been used. If across shoulder measurement and shoulder lengths are given (example: Reference Spec C), the X-axis increment is the change in half across shoulder and the Y-axis increment is the change in the shoulder length measurement plus the change in half neck width. However, if shoulder length and shoulder drop is given, the X-axis increment is the change in shoulder length plus the change in half neck width and the Y-axis increment is the change in the shoulder drop. It is thus assumed that shoulder length will increase the amount that is increased in the X or Y-axis. According to geometrical rules, however, any diagonal measurement will not increase for the amount of the increase in the X- or Y-axis. An experiment was conducted to check the effect of the diagonal measurement (e.g. shoulder length). For this experiment, patterns of the Spec A were graded using conventional Cartesian coordinate grading from the L size assumed as the base size. Bye et al. (2008) [20] confirmed that size 10 (medium size) was the optimum Table 2: Length comparisons of Spec A POMs Measurement comparison Size S M L* XL XXL Back neck drop Length required 1.50 1.50 1.50 1.50 1.50 Length acquired 1.50 1.50 1.50 1.50 1.50 Front neck drop Length required 8.00 8.50 9.00 9.50 10.00 Length acquired 8.00 8.50 9.00 9.50 10.00 Neck width Length required 16.00 17.00 18.00 19.00 20.00 Length acquired 16.00 17.00 18.00 19.00 20.00 Shoulder length Length required 15.00 16.00 17.00 18.00 19.00 Length acquired 15.10 16.05 17.00 17.96 18.92 Shoulder drop Length required 5.00 5.00 5.00 5.00 5.00 Length acquired 5.00 5.00 5.00 5.00 5.00 Armhole straight Length required 24.00 25.00 26.00 27.00 28.00 Length acquired 24.00 25.00 26.00 27.00 28.00 Sleeve arm hole straight Length required 25.00 26.00 27.00 28.00 29.00 Length acquired 25.42 26.21 27.00 27.79 28.58 Half chest Length required 48.00 51.00 54.00 57.00 60.00 Length acquired 48.00 51.00 54.00 57.00 60.00 High point shoulder Length required 70.00 72.00 74.00 76.00 78.00 Length acquired 70.00 72.00 74.00 76.00 78.00 Sleeve length Length required 21.00 22.00 23.00 24.00 25.00 Length acquired 21.00 22.00 23.00 24.00 25.00 Sleeve opening Length required 18.00 19.00 20.00 21.00 22.00 Length acquired 18.00 19.00 20.00 21.00 22.00 Under sleeve Length required 14.00 14.50 15.00 15.50 16.00 Length acquired 13.75 14.37 15.00 15.65 16.31 Note: * = Base size, Black = Length required, Blue = Exactly same, Red = Deviation from original measurements. All units are measured in cm. POM: Points of measure. 170 Tekstilec, 2020, Vol. 63(3), 166-184 base size for grading patterns in the size range of 6-14. Size 10 was selected because a common practice in grading is to select a size approximately in the middle of the size range to be graded. It can be concluded from Table 2 that all the horizontal and vertical line lengths are the same because they are plotted on the X and Y-axis respectively, as the computerised grading uses Cartesian coordinates. However, variations are found only in diagonal lines grading. Thus, diagonal measurements should be avoided as much as possible in the spec sheet because they cause grading deficiency. 2.2.2 Maintaining accuracy and matching of curve lines The computer uses Cartesian coordinates where both points have X and Y values. It is therefore always a challenge how much they should move in both directions to get the accurate curve length. The grading of a straight line is a simple process as the straight is defined by two endpoints in the computer Cartesian coordinates where both the points have X and Y values. So, it is possible to change the grading values (X, Y) in one or both points to get the desired length. However, the curve line grading is a complex process. Generally, the curve line is formed by connecting several points in the Cartesian coor- dinates location. When grade rules are applied to the endpoints of a curved edge, the program must mathematically determine how each internal curve and control point should move. The results can distort the curve. Again, in order to construct a well-made garment, the matching seam lines should be of the same length and the shape should not be distorted by the graded pattern pieces. During the grading of the curve line, the amount of change in X and Y directions to achieve the desired length of the curve is unknown. The grading increment must be adjusted several times until the desired curve length is achieved. For this experiment, all three spec-sheets (A, B and C) are selected and graded as specified, and the L size is chosen as a base size. Curve measurements are shown in Table 3. From Table 3, it can be deduced that if horizontal and vertical measurements are given, curves automatically intersect with each other. If, however, diagonal measurements are given for instance like armhole straight, the pattern grader then has to calibrate the measurements until front and back armhole curve lengths match with the front and back sleeve curve lengths. The measurements should be checked and the grading increment should be adjusted until the required curve lengths are achieved. Table 3: Comparison of curve lengths after conventional grading of different spec Combination of POMs Reference Measurement Size Unit POMs direction spec. S M L* XL XXL Front armhole curve 25.34 26.40 27.45 28.50 29.56 Vertical, Front sleeve curve 25.84 26.64 27.45 28.25 29.06 If SL, SO, AHS & US Horizontal, A Difference +0.50 +0.24 0.00 -0.25 -0.50 are given Diagonal & Back armhole curve 25.25 26.30 27.35 28.40 29.45 Diagonal Back sleeve curve 25.75 26.55 27.35 28.15 28.95 Difference +0.50 +0.25 0.00 -0.25 -0.50 Front armhole curve 25.39 26.44 27.50 28.56 29.61 Vertical, Front sleeve curve 25.90 26.70 27.50 28.30 29.10 If SL, SO, AHS & SW Horizontal, B Difference +0.51 +0.26 0.00 -0.26 -0.51 cm are given Diagonal& Back armhole curve 25.34 26.40 27.45 28.50 29.56 Horizontal Back sleeve curve 25.85 26.65 27.45 28.25 29.05 Difference +0.51 +0.25 0.00 -0.25 -0.51 Front armhole curve 25.39 26.45 27.50 28.55 29.61 Vertical, Front sleeve curve 25.40 26.45 27.50 28.56 29.63 If SL, SO, SCH& SW Horizontal, C Difference +0.01 0.00 0.00 +0.01 +0.02 are given Vertical & Back armhole curve 25.35 26.40 27.45 28.50 29.56 Horizontal Back sleeve curve 25.36 26.40 27.45 28.51 29.58 Difference +0.01 0.00 0.00 +0.01 +0.02 Note: * = Base size, Black = Length required, Blue = Exactly same, Green = Within tolerance, Red = Over tolerance limit (Explain tolerance limits) Tolerance = ± 0.20 cm, Units = Measured in cm Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations J/3 2.2.3 Selection of base size in grading If we choose jumping sizes rather than moving gradually from one size to another, some measurements often exceed the tolerance limit. The selection of the base size also has an influence over the pattern grading accuracy. Basically, there are three methods of recording the growth of the pattern: • Method 1: Progressive increment of the base size (from smallest to the largest size). • Method 2: Progressive increment or decrement of the base size to acquire all the sizes from the smallest to the largest. • Method 3: Digressive decrement of the base size to the smallest size. After evaluating the graded measurement from Table 4, it can be deduced that horizontal and vertical measurements do not change even if the base size changes. The reasoning behind is that they were plotted along X and Y axis of Cartesian coordinates. However, inclined measurements of a graded pattern are inconsistent and sometimes exceed the tolerance limit if the base size changes. Additionally, greater variations are found from the smallest and to the largest base size. So, if the middle size from the pro- vided size chart is considered as a base size (e.g. L as base size, if the size chart contains S, M, L, XL and XXL size), the errors can be minimised as they can have both positive and negative direction towards the given tolerance. So, the deficiencies of inclined measurements grading can be minimized by selecting the middle size as the base size. Another reason for the selection of the base size is the presence of breakpoint. The breakpoint of a size chart is such a measurement upon whose increment, graded pattern varies. For instance, if mentioned half-chest is 46, 48, 50, 52, 55, and 58 (units in cm) respectively for six sizes; the base size should be the size which contains half-chest 52 (units in cm), so that both sides' measurement differences would be the same. It is recommended to grade from middle size to all sizes to reduce measurement errors if diagonal measurements are given. 2.2.4 Presence of higher number of sizes Diagonal measurements relating to grading error increase as the number of sizes in the spec sheet increases. If the grading is done to get the extreme sizes, then the design, drape and fit of the garment Table 4: Length Comparisons of diagonal measurements of T-shirt Spec A POMs Size Measurement comparison Length required Tol (±) S^XXL S^L^XXL XXL^S Got Error Got Error Got Error Shoulder S 15 0.15 15.00* 0.00 15.10 +0.1 15.18 +0.18 M 16 15.95 -0.05 16.05 +0.05 16.13 +0.13 L 17 16.90 -0.10 17.00* 0.00 17.08 +0.08 XL 18 17.86 -0.14 17.96 -0.04 18.04 +0.04 XXL 19 18.82 -0.18 18.92 -0.08 19.00* 0.00 Armhole straight S 24 0.30 24.00* 0.00 24.00 0.00 24.01 +0.01 M 25 25.00 0.00 25.00 0.00 25.01 +0.01 L 26 25.99 -0.01 26.00* 0.00 26.00 0.00 XL 27 26.99 -0.01 27.00 0.00 27.00 0.00 XXL 28 27.99 -0.01 28.00 0.00 28.00* 0.00 Sleeve armhole straight S 25 0.30 25.00* 0.00 25.42 +0.42 25.84 +0.84 M 26 25.79 -0.21 26.21 +0.21 26.63 +0.63 L 27 26.58 -0.42 27.00* 0.00 27.42 +0.42 XL 28 27.37 -0.63 27.79 -0.21 28.21 +0.21 XXL 29 28.16 -0.84 28.58 -0.42 29.00* 0.00 Under sleeve S 14 0.25 14.00* 0.00 13.82 -0.18 13.63 -0.37 M 14.5 14.60 +0.10 14.40 -0.10 14.20 -0.30 L 15 15.21 +0.21 15.00* 0.00 14.78 -0.22 XL 15.5 15.84 +0.34 15.62 +0.12 15.38 -0.12 XXL 16 16.48 +0.48 16.25 +0.25 16.00* 0.00 Note: * = Base size, Black = Length required, Blue = Exactly same, Green = Within tolerance, Red = Over tolerance limit, Units: Measured in 'cm'. 172 Tekstilec, 2020, Vol. 63(3), 166-184 changes as well [6, 21, 22]. Moore et al. (2001) [23] recommend that no more than five sizes (two larger, two smaller and one base size) should be graded from the base size together using a simplified grading system; otherwise the average size range would then require multiple base sizes. A pattern should not be graded more than two sizes from the base size, so that the visual appearance remains unaffected [21]. Table 5: Measurements of two spec sheets having two different size numbers POMs Reference spec A Reference spec D Unit S M L XL XXL XS S M L XL XXL 3XL BND 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 1.50 FND 8.00 8.50 9.00 9.50 10.00 7.50 8.00 8.50 9.00 9.50 10.00 10.50 NW 16.00 17.00 18.00 19.00 20.00 15.00 16.00 17.00 18.00 19.00 20.00 21.00 S 15.00 16.00 17.00 18.00 19.00 14.00 15.00 16.00 17.00 18.00 19.00 20.00 SD 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 5.00 cm AHS 24.00 25.00 26.00 27.00 28.00 23.00 24.00 25.00 26.00 27.00 28.00 29.00 HC 48.00 51.00 54.00 57.00 60.00 45.00 48.00 51.00 54.00 57.00 60.00 63.00 HPS 70.00 72.00 74.00 76.00 78.00 68.00 70.00 72.00 74.00 76.00 78.00 80.00 SL 21.00 22.00 23.00 24.00 25.00 20.00 21.00 22.00 23.00 24.00 25.00 26.00 SO 18.00 19.00 20.00 21.00 22.00 17.00 18.00 19.00 20.00 21.00 22.00 23.00 US 14.00 14.50 15.00 15.50 16.00 13.50 14.00 14.50 15.00 15.50 16.00 16.50 Points of Measures Spec Measurement comparison Size Tol(±) XS S M L XL XXL 3XL Shoulder length A Length required - 15.00 16.00 17.00 18.00 19.00 - 0.15 cm Length acquired - 15.10 16.05 17.00* 17.96 18.92 - Error - +0.10 +0.05 0.00 -0.04 -0.08 - D Length required 14.00 15.00 16.00 17.00 18.00 19.00 20.00 Length acquired 14.16 15.10 16.05 17.00* 17.96 18.92 19.89 Error +0.16 +0.10 +0.05 0.00 -0.04 -0.08 -0.11 Armhole straight A Length required - 24.00 25.00 26.00 27.00 28.00 - 0.30 cm Length acquired - 24.01 25.01 26.00* 27.00 28.00 - Error - +0.01 +0.01 0.00 0.00 0.00 - D Length required 23.00 24.00 25.00 26.00 27.00 28.00 29.00 Length acquired 23.01 24.01 25.01 26.00* 27.00 28.00 29.00 Error +0.01 +0.01 +0.01 0.00 0.00 0.00 0.00 Sleeve armhole straight A Length required - 25.00 26.00 27.00 28.00 29.00 - 0.30 cm Length acquired - 25.43 26.21 27.00* 27.79 28.57 - Error - +0.43 +0.21 0.00 -0.21 -0.43 - D Length required 24.00 25.00 26.00 27.00 28.00 29.00 30.00 Length acquired 24.63 25.43 26.21 27.00* 27.79 28.57 29.37 Error +0.63 +0.43 +0.21 0.00 -0.21 -0.43 -0.63 Under sleeve A Length required - 14.00 14.50 15.00 15.50 16.00 - 0.25 cm Length acquired - 13.82 14.40 15.00* 15.62 16.25 - Error - -0.18 -0.10 0.00 +0.12 +0.25 - D Length required 13.50 14.00 14.50 15.00 15.50 16.00 16.50 Length acquired 13.26 13.82 14.40 15.00* 15.62 16.25 16.89 Error -0.24 -0.18 -0.10 0.00 +0.12 +0.25 +0.39 Note: * = Base size, Black = Length required, Blue = Exactly same, Green = Within tolerance, Red = Over tolerance limit, Units: Measured in 'cm'. Table 6: Length Comparisons of T-shirt Spec A and D (diagonal measurements) Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations J/3 Experts affirm that the base size should be graded no more than two sizes before another fit model is implemented and the closer the individual to the fit model standard, the fewer alterations are required. Taylor and Shoben (1990) [24] argues against the 2D system of grading and they state "fitting and balance faults will automatically occur to the graded garment range" and they also indicate that "the 2D system can be safely used for very-loose-fitting garments over a very limited size range (three sizes)". For this experiment, two spec sheets having two different size numbers were selected (Table 5). After comparing Table 2 with Table 6, it can be deduced that as the number of size increases, grading error increases as well. If the spec sheet contains 5 different sizes, the middle size should be selected [20]. But if the sizes are more than 7, then additional errors will be generated. Based on the previous studies this statement is well verified, Bye and DeLong (1994) [21] demonstrate that garment appearance and proportion are also affected when the pattern is graded more than two sizes from the base size while using standard grading practices. Moore et al. (2001) [23] recommend that no more than five sizes (two larger and two smaller) are to be graded together. The average size range would then require more than one base size. They gave examples of simplified systems that include grading information for nine sizes (three smaller and five larger than the base size), which is a common practice in the apparel industry. In accordance with the aforementioned studies, some CAD personnel in the industry generally perform the following things for minimizing grading errors instead of rectifying them. Even if number of sizes exceed 7 sizes or more, the total sizes are divided into two parts (e.g. a spec containing 10 different sizes). They thus separate them into two groups of 5 sizes each and then draw two patterns as the base size and finally grade them. However, if the size exceeds 15 sizes or more, the total sizes are divided into three groups, of which three base sizes are selected. Afterwards from the selected base size, three patterns are drawn and are then graded. It should also be noted that if it is possible to eliminate all the diagonal measurements from the spec sheet then the number of sizes in a size range does not influence the grading. Few companies within the industry fit more than one sample size, which is a common practice in the industry if garment sizes are more than five, like size 06 to size 18 with an increment of 2. 2.2.5 Combination of measurement points Some lines can be drawn using different measurement combinations. For example, the shoulder line can be drawn using any two of the three Table 7: Shoulder length comparison of different POMs combination Combination of POMs POMs direction Reference spec. Size^ S M L XL XXL Tol (±) If SD & S are given Vertical & Diagonal A Required 15.00 16.00 17.00 18.00 19.00 0.15 cm Acquired 15.10 16.05 17.00* 17.96 18.92 Error +0.10 +0.05 0.00 -0.04 -0.08 If AS & S are given Horizontal & Diagonal B Required 15.00 16.00 17.00 18.00 19.00 Acquired 15.07 16.03 17.00* 17.97 18.95 Error +0.07 +0.03 0.00 -0.03 -0.05 If AS & SD are given Horizontal & Vertical C Required 15.34 16.29 17.24 18.20 19.16 Acquired 15.34 16.29 17.24 18.20 19.16 Error 0.00 0.00 0.00 0.00 0.00 N.B. The value of column B is not given for Spec C because, according to that spec sheet, we need AS and SD to be correct. They thus must be compared them to get the shoulder. If AS & SD are given Horizontal C Required AS 45.00 48.00 51.00 54.00 57.00 0.25 cm Acquired AS 45.00 48.00 51.00 54.00 57.00 Error 0.00 0.00 0.00 0.00 0.00 Vertical C Required SD 5.00 5.00 5.00 5.00 5.00 - Acquired SD 5.00 5.00 5.00 5.00 5.00 Error 0.00 0.00 0.00 0.00 0.00 Note: * = Base size, Black = Length required, Blue = Exactly same, Green = Within tolerance, Red = Over tolerance limit, Units: Measured in 'cm'. 174 Tekstilec, 2020, Vol. 63(3), 166-184 Figure 3: Grading increment of T-shirt Spec A (body part) by changing zero point Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations 175 measurements, "Shoulder Length, Shoulder Drop and Across Shoulder Width". It must be noted that some cardinal points of the pattern (e.g. shoulder point) can be created by using different measurement combinations. For instance, a shoulder point can be created if spec sheet contains horizontal-inclined (e.g. AS and S) or vertical-inclined (e.g. SD and S) or the horizontal-vertical (e.g. AS and SD) measurement combination. However, among the three options, the horizontal-vertical combination is preferable during pattern making as the measurement changes during grading are plotted in the Cartesian coordinates. For this experiment, three spec sheets A, B and C were chosen and were graded from base size L (middle size). Table 7 clearly shows that shoulder point grading increment can be calculated without any error if horizontal and vertical POM combination is used, which can be plotted in X and Y direction respectively. The inclined graded measurement errors would not generally exceed the tolerance limit when any cardinal point of a pattern (e.g. shoulder point) is created from a horizontal-inclined (e.g. AS and S) or vertical-inclined (e.g. SD and S) measurement combination. However, better accuracy is found in the case of a horizontal-vertical combination. Horizontal and vertical POMs should be used instead of diagonal or inclined POMs to get the desired shape of the pattern. During spec sheet creation, spec sheet creators should thus use the horizontal and vertical measurements instead of inclined measurements wherever it is possible. 2.2.6 Selection of zero points The selection of a zero point is required to calculate accurate grading increment value within a minimum amount of time. At first, a zero point has to be selected to apply grade rules or grading increment values. Then the values are calculated for a different grade or cardinal points. Each pattern grading starts by identifying the grain-line, the zero point of reference, and the points where increases (or decreases for smaller sizes) are to be applied. It is necessary for any grading method to establish a point of reference for each pattern piece known as the zero point [25]. Moore et al. (2001) [23] used the centre front (and back) at the waist as the point of reference throughout their book. Vong, A. L. (2011) [4] states that "the location of the zero point on the pattern may change the grade of the pattern; additional study of whether the drape of the garment changes when the zero point is moved is needed". To check the impact of zero-point selection in grading, an experiment was conducted from spec sheet B by changing the zero point as mentioned in Table 6, as well as in Figure 3. Based on the experiment it is evident that the graded patterns consistently have the same measurements. It can therefore be concluded that the change in zero-point location does not impact the fitting unless the pattern is wrongly drafted. Consequently, the procedure was applied on the sleeve and the result remained the same. The presence of diagonal measurement produced some miscalculations, however, not due to the zero-point selection. If all the diagonal measurements are avoided, like for example in "spec C", the errors can be avoided as well. Any cardinal point can be selected as zero point. However, the calculation becomes much easier if the starting point is selected as zero-point. 2.2.7 Angle of measurement Criterion 1 of the book Sizing in Clothing written by Ashdown [25] states that "the measurement must be either horizontal or vertical". But even if the measurements are neither horizontal nor vertical, Pythagoras' law can be used for calculating grading increment properly. The angle is not a mandatory factor. In the same book it is also stated that "the measurement must be either horizontal or vertical -shifting and edge-changes grading techniques use grading information that is either horizontal or vertical; angled measurements could be used for proportional grading or could be divided into horizontal and vertical components, but only if the angle is known." However, even if the angle is not given it can be calculated from the horizontal and the vertical component of measurement. Knowing the angle is not mandatory; an example is shown in Figure 4. OB OR Figure 4: Body pattern of T-shirt (Spec A) 176 Tekstilec, 2020, Vol. 63(3), 166-184 Angle can be measured by using the following formula: Shoulder drop cos 0 =-,-T}—;-rT (1) Shoulder length , Shoulder drop 0 = cos Ti—n—;—h- (2) Shoulder length After calculation the following data were found, Table 8. In this way, it is not only possible to calculate the angle but also to reduce the grading errors. It must be noted that grading should be done manually or by using CAD software, which has an actual angle grading increment (e.g. Boke CAD) rather than employing an alternative reference line used by other software, such as Optitex, TUKA CAD, etc., which is elaborated more in section 2.2.9. If diagonal measurements, such as shoulder length or armhole straight are given, then grading anomalies can be found. So, if diagonal measurements are given along with other horizontal or vertical components, then it is possible to calculate the angle and grade them to acquire more accurate graded measurements. Table 8: Angle of shoulder slope of T-shirt body pattern (Spec A) POMs Remarks Size Unit S M L XL XXL Shoulder length? Given in Spec A 15.00 16.00 17.00 18.00 19.00 cm Shoulder drop 5.00 5.00 5.00 5.00 5.00 Angle of BCQ (Figure 4) Calculated values 70.53 71.79 72.90 73.87 74.74 Degree Angle increment -1.26 -1.11 Base -0.97 -0.87 Note: It is possible to calculate the angle of QBC also. But instead of QBC, BCQ is calculated because of angle grading by Boke CAD uses this angle, which is described in "2.2.9 Angle grading variation section" 2.2.8 Alternative reference line Some software uses an 'alternative reference line' for grading diagonal lines, but if the angle is not constant, they cannot grade the pattern accurately. Generally, the reference line for grading is parallel to the grainline but sometimes an alternative reference line not parallel to the grainline is used. Taylor and Shoben (1984), Cooklin (1990), and Mullet et al., (2009) [6, 18, 26] use alternative reference lines for different garments when simple x and y orientation can distort the pattern shape. Generally, the alternative reference line is used for the shoulder/armscye point when the dart is rotated from the shoulder position [24, 27]. Mullet et al. (2009) [6] recommend alternative grade reference lines when "a style line on the pattern piece forms an acute angle to the grade reference line (x-axis) or when grading a curve that would be distorted by using the original axis". From the above discussion, it can be deduced that the alternative reference line is only used for diagonal line grading. It is only applicable in case of most of the CAD software when the shoulders have the same angle, e.g. 17 degrees for all sizes. But if the shoulder angle varies from 17 degrees for L size to 18 degrees for XL size then most of the CAD cannot do that by Figure 5: Shoulder grading of T-shirt Spec A by alternative reference line in TUKA CAD Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations 177 Table 9: Comparison of measurement between XYgrading and alternative reference line grading of Tshirt Spec A (TUKA CAD) Points of measures (POMs) Measurement comparison Size Tol(±) S M L XL XXL Shoulder length Error with XY increment +0.07 +0.03 0.00 -0.03 -0.05 0.20 cm Length with XY increment 15.07 16.03 17.00 17.97 18.95 Length required 15.00 16.00 17.00* 18.00 19.00 Length with alternative reference line 14.96 15.98 17.00 18.02 19.05 Error with alternative reference line -0.04 -0.02 0.00 +0.02 +0.05 Shoulder drop Error with XY increment 0.00 0.00 0.00 0.00 0.00 0.00 cm Length with XY increment 5.00 5.00 5.00 5.00 5.00 Length required 5.00 5.00 5.00* 5.00 5.00 Length with alternative reference line 4.12 4.56 5.00 5.44 5.88 Error with alternative reference line -0.88 -0.44 0.00 +0.44 +0.88 Note: * = Base size, Black = Length required, Blue = Exactly same, Green = Within tolerance, Red = Over tolerance limit, Units: Measured in 'cm'. alternative reference line, which is actually known as "Angle grading" as it will distort the across shoulder or shoulder drop measurement. It is evident from the findings of Table 9 that alternative reference line grading cannot solve the grading problem. If the angle is constant, then the usage of Optitex or TUKA CAD's alternative reference line grading is recommended. 2.2.9 Angle grading variation Sometimes shoulder slope angle is not constant throughout all the sizes, so it results in grading error if alternative reference line grading is used. Alternative reference line is actually known as 'angle grading' in apparel CAD software. Angle grading varies in different software such as TUKA CAD, Optitex etc. CAD system uses an alternative reference line in angle grading, whereas Boke CAD uses actual angle increment in angle grading. Examples are shown in Figure 6. From the Table 10, it is clear that the actual angle grading can solve the grading problem. If the angle remains inconstant then the use of Boke CAD's angle grading, instead of alternative reference line grading by Optitex, TUKA CAD software, etc is advised. 2.2.10 Selection of grade point or absence of certain measurements Different shaping errors (e.g. armhole shape curve) occur due to the absence of some measurement points. Grade point or cardinal points are those points that are present at the perimeter of the pattern and distribute the changes in body dimension [4]. Grade points are also known as cardinal points [6]. Solinger, (1988) [28] states that "when grading, the 'essence' of a garment should be maintained through all sizes". Doyle and Rodgers (2003) [17] state the importance of keeping the curves of the base pattern consistent: "If the grader changes the shape of the curve, the fit of the garment changes". Taylor and Shoben (2004) [18] state that while grading the armhole shape, "the angles at the cardinal point on the pattern must remain the same on all sizes". After grading, seam lines of the Figure 6: Shoulder grading of T-shirt spec A by actual angle grading in Boke CAD 178 Tekstilec, 2020, Vol. 63(3), 166-184 Table 10: Comparison of measurement between XYgrading and angle grading of T-shirt spec A by Boke CAD (shoulder length and shoulder drop) Points of Measures Measurement comparison Size Unit (POMs) S M L XL XXL Error with XY increment +0.10 +0.05 0.00 -0.04 -0.08 Length with XY increment 15.10 16.05 17.00 19.96 18.92 Shoulder Length Length Required 15.00 16.00 17.00* 18.00 19.00 Length with angle grading 15.00 16.00 17.00 18.00 19.00 Error with angle grading 0.00 0.00 0.00 0.00 0.00 cm Error with XY increment 0.00 0.00 0.00 0.00 0.00 Length with XY increment 5.00 5.00 5.00 5.00 5.00 Shoulder drop Length Required 5.00 5.00 5.00* 5.00 5.00 Length with actual angle 5.00 5.00 5.00 5.00 5.00 Error with actual angle 0.00 0.00 0.00 0.00 0.00 Note: * = Base size, Black = Length required, Blue = Exactly same, Green = Within tolerance, Red = Over tolerance limit, Units: Measured in 'cm'. graded pattern should be checked to ensure that they are of the same length during sewing. Some spec sheets provide measurements for across chest and back. Occasionally, such measurements are absent in some spec sheets. In that case, pattern makers construct front and back armhole curve lines from shoulder point to underarm point. Sometimes the shape of armhole curves might be imperfect due to the absence of armhole curve depth, i.e. absence of across chest and across back measurements. And if these measurements are not given, the grading increment values for middle point of the curves (e.g. across chest and across back point) remain unknown. Different examples of armhole curve shapes are shown in Figure 7, indicated by red, green and blue colour. If the across chest and across back measurements are provided in the spec sheet, the curves become more precise. When the curves are drawn from the shoulder point, across chest or across back and underarm point to avoid the fitting problem the curves do not require readjustment for adjacent sizes as then grading increment values can be calculated. In short, across chest and across back measurements are to be used for drawing armhole shape curves accurately. Most of the time, pattern shape related problems occur due to the absence of curve depth. So, if AC and AB are given, then armhole shape curves can be drawn through three points: shoulder point, across chest/across back point and armpit point. Across chest and across back measurements should be used for drawing armhole shape curves. For better armhole shape, the following things can be done: • Manual drawing by French curve [29] • Saving and selection of curve (e.g. Gemini CAD French curve tool) 2.2.11 Absence of measurement location If some measurements are absent in the spec sheet (e.g. across chest and across back position) or even a) b) Figure 7: a) Tentative armhole curve from shoulder point to armpit point without across chest and across back; b) accurate armhole curve from shoulder point to armpit point with across chest and across back measurements Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations 99 ............. - — m HjKNImlndmciiva A HJxMMwactftc mi** WJadeel iridet -J»«*itr.c W-jKtai ico ifcw iim WJ»:I.M Mtk ™-„i WJ«UtbMkAMk*Wi VMt&eHwqcwv* MJWÄÖttlXkl» MTiOrtcrfrfrcfltrte WTi.•••• F,orlAirM.Cuv, DiWB I RÎHWT* I Oowtj Up I FfcX | FfeY | 0k | Cared | a) b) Figure 8: a) French curve and their uses for manual armhole curve drawing; b) saving and selection of curve by Gemini CAD French curve tool in the standard measurement chart, the shape of the pattern changes and fitting problems occur. Some spec sheets have across chest and back but do not have their vertical position from HPS. Sometimes, they are not properly clarified in standard measurement charts. Different pattern making books provide different guidelines on how to make the vertical position of across chest and back measurements. Different armhole curves were therefore drawn indicating different colours in Figure 9 according to the different procedures, which are mentioned below. In the developed method, across chest position from armpit point (X-Y, in Figure 10) is one-third of arm-scye depth (W-X, in Figure 10) and across back position from armpit point (XX-YY, in Figure 10) is one-third of armscye depth (WW-XX, in Figure 10). It can be concluded from Figure 9 and Figure 10 that green and red colour give more accurate shapes. For better armhole curve shape, the across chest and across back position should be drawn by dividing the armscye depth into two-third of its original length from the neck point, if across chest and across back position are absent. Figure 9: Front bodice and back bodice with five different armhole curve shapes constructed with different procedures Table 11: Colour code of armhole curve, including developed method for across chest and back position Colour code Method Red developed method Blue Helen Joseph Armstrong (2010)[30] Green Winifred Aldrich (2008) [31] Pink Bina Abling and Kathleen Maggio (2008) [32] Gold http://fashionauntie.blogspot.com/2012/02/first-stages-of-pattern-drafting-for.html [33] 180 Tekstilec, 2020, Vol. 63(3), 166-184 Figure 10: Front and back part of bodice block [developed method] 2.2.12 Lack of proper drafting procedure Inadequate drafting procedure can sometimes lead to grading errors as the grading relates to the pattern making procedure. Sometimes buyers gave us a soft copy of a pattern along with the spec sheet. Then the pattern maker graded the pattern. So, if the drafting procedure is unknown to the grader, grading errors are plausible. On some other occasions, buyers gave us a soft copy of pattern along with the spec sheet but without any natural waist length (NWL) measurement (Figure 11). Different pattern makers use different techniques to meet the standard length of given measurements in the spec sheet, if it is absent in the spec sheet. For instance, some pattern makers use "2/3 of the total body length from high point of shoulder to ^ waist Start a; B) Figure 11: Different drafting procedure of NWL Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations 181 position" for calculating NWL if it is not provided in the spec sheet. According to the 8 head theory, the NWL position is the second head position from the neckline, and hip position is the third head position (Figure 11A). Other pattern makers use half of the side seam measurements (Figure 11B). So, if any measurement or procedure is unknown to the grader it then becomes very difficult to grade the pattern with accurate measurement. It can be concluded from Figure 11 that if the procedure is unknown to the grader it leads to grading errors as grading increment value depends on the pattern drafting procedure. When manufacturers only need to grade the pattern, the grader should be familiar with the procedure unless the grading increment values are provided in the Tech Pack. 2.2.13 Non-identifiable body landmarks or unusual measurement Some measurements used in the spec sheet do not relate to the identifiable body landmarks. Furthermore, measurements are sometimes unknown to the majority of pattern makers. Different pattern makers use different methods along with different measurements for the same design. But some measurements used in the body measurement chart are not related to the identifiable body landmarks. For example, a world-famous pattern maker Helen Joseph Armstrong (2010) [30] uses 'new strap measurement' (Figure 12), which is neither used by any pattern maker nor present in any body-measurement chart. Though Helen Joseph Armstrong's (2010) [30] method gives the best fitting due to unconventional measurement, it would be difficult to grade the pattern. As seen in Figure 12, the measurement is neither perfectly diagonal nor a curve measurement, which can be measured through some definite points. In pattern making such measurements should be used that do not impact the grading and unusual measurements should therefore be avoided if they cause grading deficiencies. 2.2.14 Manual vs. computerised method of grading Manual grading is a time-consuming and troublesome process whereas computerised grading is much more convenient and precise. Often, the accuracy of the graded pattern pieces of clothing is affected by grader's skill [34]. The manual procedure of grading is exceptionally tedious and grading efficiency is affected by grader's experience [14]. Although the 2D CAD system provides time-saving solutions, they are not free from limitations. The grade rule creation or grading increment calculation is used by all types of 2D CAD system for apparel. But to complete the grading process, manual calculation and inputs are required for 2D CAD [14]. Computerised pattern grading is the most precise and expedient method but only when the accurate values are entered into the computer [6]. It is evident that manual grading is less efficient than the computerised method and usage of computerised grading is therefore recommended if possible. A) B) C) Figure 12: List of some non-identifiable body measurements. A - new strap, B - front shoulder slope, C - back shoulder slope 182 Tekstilec, 2020, Vol. 63(3), 166-184 3 Results and discussion After conducting all grading experiments, different problems are identified and finally, some recommendations are given for every problem. Different kinds of spec sheets were provided by different buyers with different POM variations. So, it is necessary to learn the proper grading calculation method and how the patterns are actually made from different measurements. Grade rule calculation has to be done in such a way that minimum measurement errors occur from graded pattern pieces and also, styles features left intact. The recommendations are given so that pattern graders can use them as a reference or guideline to avoid unnecessary grading problems. 3.1 General recommendations i. Presence of diagonal measurements. The diagonal measurements should be avoided as much as possible in the spec sheet because they cause grading deficiency. ii. Maintaining accuracy and matching of curve lines. Measurement checking and optimisation of the grading increment should be done until the required curve lengths are achieved. iii. Selection of base size. If diagonal measurements are provided, then grading should be done from middle size to all sizes in order to reduce measurements errors. iv. Presence of higher number of sizes. If the spec sheet contains 5 to 7 sizes, the middle size should be selected. If the number of sizes exceeds 7 or more, then the total number of sizes should be divided into two parts, and two base sizes should be selected. Afterwards, grading should be done by drawing two separate patterns. Even if the number of total sizes exceeds 15 or more, the total sizes should be divided into three individual parts. And then by selecting three base sizes, three individual patterns are to be drawn and later graded. It should also be noted that if it is possible to eliminate all the diagonal measurements from the spec sheet then the number of sizes in a size range does not influence the grading. v. Combination of measurements. Horizontal and vertical POMs should be used instead of diagonal or inclined POMs to achieve the desired shape of pattern wherever possible. During the crea- tion of spec sheets, spec sheet creators should use horizontal and vertical measurements instead of inclined measurements wherever possible. vi. Selection of zero points. Any cardinal point can be selected as zero point but if the starting point is selected as zero-point, the calculation becomes easier. The starting point should therefore be chosen as zero point. vii. The angle of measurement. If diagonal measurements, such as shoulder or armhole straight are given, then grading anomalies are found. If diagonal measurements are provided along with other horizontal or vertical components, then it is possible to calculate the angle and grade them to get more accurate graded measurements. viii. Alternative reference line. If the angle is constant, then the usage of Optitex or TUKA CAD's alternative reference line grading is recommended. ix. Angle grading variation. If the angle is not constant then the usage of Boke CAD's angle grading instead of alternative reference line grading by Optitex, TUKA CAD software etc. are advised. x. Selection of grade point or absence of certain measurements. Across chest and across back measurements are to be used for drawing armhole shape curves. For better armhole shape, the following recommendations can be employed: A) Manual drawing by French curve, B) Saving and selection of curve (e.g. Gemini CAD French curve tool). xi. Absence of measurement location. For better armhole curve shape, the across chest and across back position should be drawn by dividing the armscye depth into 2/3 from neck point if across chest and across back position are not given. xii. Lack of proper drafting procedure. When manufacturers only need to grade the pattern, the procedure should be well-known to the grader unless the grading increment values are provided in the Tech Pack. xiii. Non-identifiable body landmarks or unusual measurement. Unusual measurements should be avoided if they cause grading deficiencies. xiv. Manual vs. computerised method of grading. It is evident that manual grading is less efficient than a computerised method, so it is recommended to use computerised grading if possible. Assessment of the Factors Affecting Apparel Pattern Grading Accuracy: Problems Identification and Recommendations 183 4 Conclusion Pattern grading is the most popular method in ready-made garment industries for large scale manufacturing of different sizes, even though grading calculation can sometimes be complex. Grading is still popular because it is less time consuming and cost-efficient in making different sized patterns during production. However, defective grading affects other computerised downstream operations, such as computerised marker making and computerised cutting. It is important to note that although computer-aided applications contributed to minimising production costs and improving manufacturing efficiency, it cannot satisfy the customer's need for individualisation. Although grading calculation is very complex, patterns can be graded successfully without errors and distortion of style features, if the calculation is done properly. It will not only reduce the sample approval time, but will also help us to create clothing that fits better on the wearer's body. References 1. JALIL, Mohammad Abdul, HOSSAIN, M. Tanjim, ISLAM, M. Mazharul, RAHMAN, M., ROY, P. To estimate the standard minute value of a polo-shirt by work study. Global Journal of Researches in Engineering, 2015, 15(2), 25-26. 2. ISLAM, Mazharul, HOSSAIN, Tanjim, JALIL, Mohammad Abdul, KHALIL, Elias. Line balancing for improving apparel production by operator skill matrix. International Journal of Science, Technology and Society, 2015, 3(4), 101-106, doi: 10.11648/j.ijsts.20150304.11. 3. SCHOFIELD, Nancy A., LaBAT, Karen L. Defining and testing the assumptions used in current apparel grading practice. Clothing and Textiles Research Journal, 2005, 23(3), 135-150, doi: 10.1177/0887302X0502300301. 4. VONG, Ann Louise [online]. An investigation of the relationship between fabric grain orientation and pattern grading : Master thesis, 2012 [cited 07.05.2020]. Available on World Wide Web: . 5. PATERSON, M. I. Pattern grading by computer. University of Bradford, 1978 [unpublished thesis]. 6. MULLET, Kathy K. Concepts of pattern grading: techniques for manual and computer grading. New York : Bloomsbury Publishing, 2009. 7. FONTANA, Marzia, RIZZI, Caterina, CUGINI, Umberto. 3D virtual apparel design for industrial applications. Computer-Aided Design, 2005, 37(6), 609-622, doi: 10.1016/j.cad.2004.09.004. 8. ASHDOWN, Susan P., DUNNE, Lucy. A study of automated custom fit : readiness of the technology for the apparel industry. Clothing and Textiles Research Journal, 2006, 24(2), 121-136, doi: 10.1177/0887302X0602400206. 9. BEAZLEY, Alison, BOND, Terry. Computer-aided pattern design and product development. Oxford : Blackwell, 2003. 10. LIM, Hosun, ISTOOK, Cynthia L. Automatic pattern generation process for made-to-measure. Journal of Textile and Apparel, Technology and Management, 2012, 7(4), 1-11. 11. KIM, Sungmin, PARK, Chang Kyu. Basic garment pattern generation using geometric modelling method. International Journal of Clothing Science and Technology, 2006, 19(1), 7-17. doi: 10.1108/09556220710717017. 12. PETRAK, Slavenka, ROGALE, Dubravko, VINKO, Mandekic-Botteri. Systematic representation and application of a 3D computer-aided garment construction method-Part II: Spatial transformation of 3D garment cut segments. International Journal of Clothing Science and Technology, 2006, 18(3), 188-199, doi: 10.1108/09556220610657952. 13. YANG, Yunchu, ZHANG, Weiyuan. Prototype garment pattern flattening based on individual 3D virtual dummy. International Journal of Clothing Science and Technology, 2007, 19(5), 334-348. doi: 10.1108/09556220710819528. 14. LIU, Z., HARLOCK, S. C. A Computer-Aided Grading System for Both Basic Block and Adapted Clothing Patterns: Part II: The Grading Algorithms. Textile Research Journal, 1995, 65(2), 95-100. doi: 10.1177/004051759506500205. 15. ROHR, Mayer. Pattern drafting & grading: women's and misses garment design, including junior's, sub-teens, teens, and half sizes. Rohr Publishing, 1961. 16. HANDFORD, Jack. Professional pattern grading for women's, men's and children's apparel. Redondo Beach : Plycon Press, 1980. 17. DOYLE, Moira, RODGERS, Jason. Essentials of pattern grading : the projection of cartesian coordinates into a spherical geometry of fractal order 2.5 using collinear scaling as the algebraic matrix—clarified. Los Angeles : Hanover Phist, 2003. 184 Tekstilec, 2020, Vol. 63(3), 166-184 18. SHOBEN, Martin M., TAYLOR, Patrick. Grading for the fashion industry: the theory and practice. LCFS Fashion Media, 2004. 19. SCHOFIELD, N. A. Pattern grading. In Sizing in clothing: developing effective sizing systems for ready-to-wear clothing. Edited by S.P. Ashdown. Cambridge : Woodhead Publishing, 2007, 152-198. 20. BYE, E., LABAT, K., MCKINNEY, E., KIM, D.-E. Optimized pattern grading. International Journal of Clothing Science and Technology, 2008, 20(2), 79-92. doi: 10.1108/09556220810850469. 21. BYE, Elizabeth K., DELONG, Marliyn R. A visual sensory evaluation of the results of two pattern grading methods. Clothing and Textiles Research Journal, 1994, 12(4), 1-7, doi: 10.1177/0887302X9401200401. 22. SCHOFIELD, Nancy, LABAT, Karen L., Exploring the relationships of grading, sizing, and anthropometric data. Clothing and Textiles Research Journal, 2005, 23(1), 13-27. doi: 10.1177/0887302X0502300102. 23. MOORE, C. L., MULLET, Kathy K., YOUNG, M. P. Concepts of pattern grading. New York : Fairchild Books, 2001. 24. TAYLOR, Patrick J., SHOBEN, Martin M. Grading for the fashion industry : the theory and practice : second edition with childrens and mens wear. Nelson Thornes Publishing, 1990. 25. Sizing in clothing. Edited by S. ASHDOWN. Cambridge : Woodhead Publishing, 2007, 173-174. 26. COOKLIN, Gerry. Pattern grading for women's cloth : the technology of sizing. Oxford : BSP Professional Books, 1990. 27. COOKLIN, Gerry. Pattern grading for children's clothes : the technology of sizing. Oxford : BSP Professional Books, 1991. 28. SOLINGER, Jacob. Apparel manufacturing handbook : analysis, principles, and practice. Columbia, SC : Bobbin Media Corp., 1988, 105-109. 29. ZANDGHOREISHI, Monir. Basic pattern drafting [online]. KS School of Design [accessed 07.05.2020]. Available on World Wide Web: . 30. ARMSTRONG, Helen Joseph. Patternmaking for fashion design. Pearson Publishing, 2010, 40-43. 31. ALDRICH, Winifred. Metric pattern cutting for women's wear. 5th ed. John Wiley & Sons, 2008, 16-20. 32. BINA, Abling, KATHLEEN, Maggio. Integrating draping, drafting, and drawing. Fairchild Books, 2009, 68-73. 33. Start by drafting a basic bodice block [online]. Fashion Auntie [accessed 31.03.2020]. Available on World Wide Web: . 34. KANG, Tae J., KIM, Sung Min. Development of three-dimensional apparel CAD system : part 1 : flat garment pattern drafting system. International journal of clothing science and technology, 2000, 12(1), 26-38, doi: 10.1108/ EUM0000000005318. Tekstilec, 2020, Vol. 63(3), 185-194 | DOI: 10.14502/Tekstilec2020.63.185-194 185 Sukhvir Singh Mody University of Science and Technology, School of Design, First Street, 512, ABB Building, Lakshmangarh, Rajasthan 332311 India Development of a Collection of Garments Inspired by the Hawa Mahal Historical Monument Razvoj kolekcije oblačil, navdihnjene z zgodovinskim spomenikom Hawa Mahal Short scientific article/Kratki znanstveni prispevek Received/Prispelo 5-2020 • Accepted/Sprejeto 6-2020 Corresponding author/Korespondenčni avtor: Sukhvir Singh E-mail: sukh7911@gmail.com ORCID: 0000-0002-4010-5291 Abstract Sources of inspiration play a vital role during the initial stages of the fashion design process by providing a specific direction to the entire fashion design process. Fashion designers interpret their imagination to improve the creative use of design inspirations during the development of clothing collections. Such exploration for design inspiration is crucial in the fashion design process for absorbing visual ideas and translating them into original creative clothing. The uniqueness of such creatively and systematically designed original clothing will also improve significantly. The current study focuses on the systematic development of a collection of casual women's wear inspired by the Hawa Mahal (The Palace of Winds) historical monument in Jaipur, Rajasthan. The fabric patterns were developed by extracting motifs from the Hawa Mahal architectural marvel using computer-aided designing solutions and digital printing with hand embroidery. In order to check the market potential of developed garments, a mini-survey was also conducted to analyse the extent of the appropriateness of garment silhouettes, fitting and drape, and overall aesthetic features among targeted consumers. Keywords: fabric pattern design, historical motif, clothing collection Izvleček Viri navdiha igrajo ključno vlogo v začetnih fazah modnega oblikovanja, tako da določijo smer celotnemu procesu modnega oblikovanja. Modni oblikovalci interpretirajo svojo domišljijo z namenom, da bi izboljšali kreativno uporabo oblikovalskega navdiha za razvoj kolekcije oblačil. Takšno raziskovanje oblikovalskega navdiha je ključnega pomena pri modnem oblikovanju, in sicer za dojemanje vizualnih idej in njihovo prevajanje v izvirna kreativna oblačila. Tako se edinstvenost takšnih ustvarjalno in sistematično zasnovanih izvirnih oblačil tudi bistveno izboljša. Ta študija se osredinja na sistematičen razvoj kolekcije sproščenih ženskih oblačil, ki jih je navdihnil zgodovinski spomenik Hawa Mahal Palača vetrov iz Džaipurja v Radžastanu. Vzorci tkanin so bili razviti na podlagi motivov iz arhitekturnega čudesa Hawa Mahal z uporabo računalniško podprtih oblikovalskih rešitev in uporabo digitalnega tiska z ročnim vezenjem. Za preverjanje tržnega potenciala razvitih oblačil je bila izvedena manjša anketa med ciljnimi potrošniki, da bi ugotovili ustreznost silhuet oblačil, prileganja in drapiranja ter splošnih estetskih lastnosti. Ključne besede: oblikovanje vzorcev tkanin, zgodovinski motiv, kolekcija oblačil 186 Tekstilec, 2020, Vol. 63(3), 166-184 1 Introduction The fashion design process is the systematic and sequential creative activity of incorporating research from different sources, analysing scrutinized inputs and utilising the information effectively and efficiently to achieve the desired outcome [1-4]. A fashion designer seeks inspiration from various natural sources, such as flora and fauna, and from architectural monuments and the virtual world [5-6]. One of the key characteristic quality features of a successful fashion designer is the ability to be a good absorber of visual ideas, creative thinker and skilled interpreter. In order to achieve the desired output, a fashion designer should be able to utilize the inputs from different sources in line with design principles and design empathy. Such practice is crucial to improving creativity, originality and uniqueness in a design [7-8]. In the process of apparel range development, the sources of design inspiration play a significant role by providing the right direction to the entire early design process [9]. Unlike other previously developed products, new product development also includes design taking into account functionality, aesthetics and expressiveness [10]. Thus, a uniquely designed product reveals many things about the visual perception of the designers. Fashion designers anticipate trending styles, colours, silhouettes and materials based on the outcome of their research and observations from numerous sources. Architectural monuments, including historical monuments, can also serve as great sources of inspiration for fashion designers [11-13]. There exists a strong connection between fashion and architecture due to similarities in the design process and equal applications of basic design elements and principles. According to the famous designer Coco Chanel, "Fashion is architecture: it's a matter of proportion" [14]. Modern architecture or a historical monument can be a great source of garment silhouettes, derived motifs and patterns [15-16]. In the recent past, many renowned fashion designers also took inspiration from architectural monuments [17-19]. The Hawa Mahal, known as the Palace of Winds, is a major tourist attraction of the UNESCO world heritage city Jaipur, Rajasthan. It is also known as the pride of the pink city Jaipur due to its unique architectural resemblance to the honeycomb structure of a pyramid shape. The Hawa Mahal was specially designed for queens who gazed outside through the 953 perforated windows (Jharokhas) that keep the Hawa Mahal cool. The Hawa Mahal was constructed in 1799 by Maharaja Sawai Pratap Singh from red and pink sandstone [20]. Due to the characteristic features of the Hawa Mahal, it is not just an architectural marvel of Jaipur, but also a great source of inspiration for designers. This study focuses on the development of a collection of casual wear for women inspired by the famous Hawa Mahal historical monument situated in state capital Jaipur of Rajasthan. The focus of the current study was more on deriving and developing motifs for an apparel range inspired by the Hawa Mahal. The patterns of the garment collection was developed after deriving, scrutinizing and analysing the development of the motif using computer-aided design. The process of motif development requires a great deal of effort, scrutiny and patience. Once the motifs were ready, it was comparatively easier to convert these developed motifs into desired patterns. The development of fabric appearance was carried out using digital printing and hand embroidery techniques. Consumer behaviour was also observed by conducting market research in order to analyse the market potential of products in terms of garment silhouettes, drape and fitting and the overall aesthetic features of developed garments. 2 Materials and methods 2.1 Material Due to the exceptional comfort properties of cotton, 100% cotton fabric of 125 g/m2 (GSM) was used for the final development of a collection comprising five garments. The cotton fabric was sourced from the local market of the city of Jaipur. The women's casual wear collection produced using breathable cotton fabrics also meets the requirements of targeted consumers of Jaipur, Rajasthan. That casual wear is also the preferred choice of consumers for summer wear for hot and humid Indian tropical conditions. 2.2 Methods An eight-step new product development process was considered for the development of a range of women's casual summer wear. Those eight steps include idea generation, idea screening, concept development and testing, marketing strategy development, business analysis, product development, market testing and commercialisation [21-22]. Idea generation and idea screening help in filtering infeasible ideas through brainstorming. Developing a concept focuses on design and features, whereas developing a marketing Development of a Collection of Garments Inspired by the Hawa Mahal Historical Monument 18/ strategy deals with identifying the target market, product positioning, pricing and distribution, and marketing communication. Business analysis is performed to verify the economic viability of the concept by projecting sales and profit. Moreover, a product is developed and initially tested on the market on a small scale before product commercialisation. Among all involved steps, a few steps, such as a part of business analysis and product commercialisation, were kept optional and skipped due to study feasibility limitations. In order to observe and analyse the taste of targeted consumers of the city of Jaipur, a mini-survey was conducted among young females aged 18-25 years. The control factors considered for this survey were garment silhouettes, garment drape and fit, and the overall aesthetic features of the garment. The frequency of respondents' responses in terms of acceptance was recorded individually for each garment. A total of 500 respondents from various background (students, corporate sector employees and academic professionals) shared their feedback in the mini-survey, which was conducted to observe and analyse the market potential of the developed garments during the initial stage. For each garment sample, 100 randomly selected respondents were asked to give a score out of 100 for control factors, such as garment silhouettes, fitting and drape, and the overall aesthetics of the garment. The mean value of these 100 readings was determined for individual garments and expressed in percentages, as shown in Table 1 in the results and discussion section. Clothing comfort is crucial when selecting a garment silhouette for modern targeted consumers. Garment silhouettes with a wide-cut were incorporated to facilitate better movement and improved air permeability. The focus of this study was deriving and developing motifs using computer-aided design and then depicting scrutinized motifs on fabric using digital printing and hand embroidery techniques. Digital printing was selected for depicting developed motifs because of the higher accuracy of the print quality. Along with digital printing, hand embroidery was considered an effective tool for additional surface embellishment and is very popular among local consumers. 3 Results and discussion 3.1 Motif development In this study, the motifs were derived and developed using computer-aided design software, including Adobe Illustrator and Optitex PDS from the source of inspiration, which was the Hawa Mahal historical monument. In the initial stage, photographs of Figure 1: Royal women gazing through the iconic "Jharokha" window of the Hawa Mahal 188 Tekstilec, 2020, Vol. 63(3), 166-184 some unique and inspiring elements and sequences were taken by visiting Hawa Mahal. A motif of royal women gazing through the uniquely designed "Jharokha" windows of the Hawa Mahal depicts the richness of the 18th century costumes of royal women from Jaipur, Rajasthan, as shown in the Figure 1. The second scrutinized motif used for pattern development was a motif inspired by the uniquely designed iconic "Jharokha" windows of the Hawa Mahal, which serve as the smallest unit of repetition in the honeycomb structure of the front side of the Hawa Mahal. It consists of one main window in the front and two relatively smaller side windows, as shown in Figure 2. The motif developed for creating a pattern is shown in Figure 2, together with a pigeon. A pigeon is included here because, in front of the Hawa Mahal, hundreds of pigeons sit on the electric wires outside of this architectural marvel at all times. These birds sitting on the wires add beauty to the Hawa Mahal, as "the birds seem motionless as if in meditation," described Gulzar [23]. Among many other developed motifs, the third motif is a depiction of the front view of theHawa Mahal, which is a honeycomb structure made up of the repetition of rows and columns of the iconic "Jharokhas" windows of the Hawa Mahal,as shown in Figure 3. Figure 2: Motif developed (left) from the iconic "Jharokha" windows (right) of the Hawa Mahal Figure 3: Honeycomb structure created (left) inspired by "Jharokhas" used in the Hawa Mahal (right) Development of a Collection of Garments Inspired by the Hawa Mahal Historical Monument 18/ 3.2 Fabric pattern design The developed and scrutinized motifs were then printed on good-quality 100% cotton fabric purchased from the local market. When selecting printing techniques, digital printing was selected over to other printing techniques due to the desired print accuracy and good overall print quality on the fabric. Apart from digital printing, hand embroidery using basic stitches, such as a simple running stitch, cross stitch, etc. was also adopted for further fabric surface embellishment. Hand embroidery was also incorporated due to the huge demand for such products among the targeted consumers of the Jaipur region. A piece of the sample depicting the conversion of the developed motif to printed and embroidered fabric surface is shown in Figures 4-7. Figure 4: Motif developed (left) depicting royal women gazing through "Jharokha" Figure 5: Pattern developed on fabric surface (left) using a developed motif (right) 190 Tekstilec, 2020, Vol. 63(3), 166-184 Figure 6: Developed motif (left) and prepared fabric samples (right) Figure 7: Pattern development using CAD (left) and fabric surface developed (right) 3.3 Garment collection planning and development Garment collection planning was carried out meticulously and systematically through sufficient research and after incorporating suggestions from previous studies. A detailed study was conducted to select garment silhouettes, colour combinations, variations in products, fitting and drape, and the overall aesthetic features of the final garments. Initially, a garment collection was developed using basic computer-aided design solutions, such as Adobe Illustratorand Optitex PDS. Toile garment samples were prepared in order to determine the silhouette directions of the garments. The final five garments of the women's summer wear collection were produced applying minimal variation from predefined styles and silhouettes, as shown in Figure 8. The garment collection was produced using 100% cotton fabric with a weight of 125 g/m2, which is suitable for summer wear. The patterns developed using computer-aided designs were then printed using a Yuhan-Kimberly digital printer. The patterns of the printed fabrics were then cut and sewn using an industrial grade JUKI machine according to predefined sizes and silhouettes. Finally, hand embroidery was performed using different stitches on some selected motifs of different garments. Development of a Collection of Garments Inspired by the Hawa Mahal Historical Monument 18/ Figure 8: Garment collection developed using CAD (above) and developed garments (below) It was observed that the use of computer-aided design helps in a more accurate visual interpretation of creative ideas by improving the originality and uniqueness of the designs. The use of digital printing for fabric surface development further improves design accu- racy using a Yuhan-Kimberly digital printer. Hand embroidery was used to enhance the attractiveness and emphasise parts of the developed fabric surface. A few enlarged motifs samples prepared using different stitches of hand embroidery are shown in Figure 9. 192 Tekstilec, 2020, Vol. 63(3), 166-184 3.4 Market potential of developed garment collection In the process of new product development, the market product potential of a product should also be verified. Thus, all five garment styles were tested for responses, such as the acceptance of silhouettes, garment drape and fitting, and overall aesthetics among targeted consumers of the Jaipur region. Based on the collective mean score of an individual garment, it was found that garment G2 (shown in Figure 8) scored highest, followed by garment G1 and garment G4, as shown in Table 1. The lowest collective mean score was observed in the case of garment G3 due to inappropriate silhouettes, drape and fitting, and poor overall aesthetic features, which was confirmed from visuals and from experimental results. The reasons behind the exceptionally good market potential of garment G2 were attractive garment silhouettes, better drape and enhanced overall aesthetics, contributing to improved consumer satisfaction relative to other garments. The results of the observed mean score for different control variables is shown in Table 1. Table 1: Control variables and observed mean scores of garments Contributing factors Mean score Garment 1 (G1) Garment 2 (G2) Garment 3 (G3) Garment 4 (G4) Garment 5 (G5) Silhouettes 78.14 76.47 49.66 68.56 61.43 Garment drape andfitting 81.67 84.11 51.91 76.77 67.58 Overall aesthetics 73.45 83.34 54.73 71.34 64.45 Total mean score of garment 77.75 81.30 52.10 72.22 64.48 Development of a Collection of Garments Inspired by the Hawa Mahal Historical Monument 18/ 4 Conclusion The new product development process was adopted for a range of women's summer wear inspired by the Hawa Mahal architectural marvel and historical monument. It was observed that computer-aided design is an effective and efficient way of interpreting the visual idea of the creative mind of the designers. Scrutinised motifs and subsequent patterns were extracted from the front view of the honeycomb structure of the Hawa Mahal using computer-aided design solutions. It was found that a digital printing technique was an effective approach to fabric pattern development. Basic hand embroidery was also incorporated to satisfy the requirements of target consumers, and was found to have a significant impact on the overall aesthetic features of the garment. The findings pertaining to the market potential of the developed garments reveal that garment G2 (81.30) achieved the highest collective mean score, followed by garment G1 (77.75) and G4 (72.22). These garments thus have a positive impact on used control variables among targeted consumers and reflect product success. The factors contributing to the promising market potential of these garments were attractive silhouettes, good garment drape and fit, and the appealing overall aesthetic features of the garments. Garment G3 (52.10) achieved the lowest collective score, as the merchandise failed to attract target consumers due to inappropriate garment silhouettes, fit and poor overall appearance. The current study was primarily conducted to understand the garment range development process using computer-aided design and the possible marketing feasibility of the developed range of garments. When conducting the survey, only a few imperative factors were considered. However, many other equally important factors, such as colour combination and psychological factors, may also be included in further research. Acknowledgement I would like to express my deep gratitude to Prof. (Dr.) Smriti Agarwal and Ms. Sanskriti Sharma of the School of Design, Mody University for their support at various stages of this study. References 1. CROSS, N. Designerly ways of knowing: design discipline versus design science. The 1920s and the 1960s, two important periods in the modern history of design. Design Issues, 2001, 17(3), 49-55, doi: 10.1162/074793601750357196. 2. SIMON, H.A. The science of the artificial. Cambridge, MA: MIT Press, 1969. 3. SCHON, D.A. The reflective practitioner: how professionals think in action. New York: Basic Books, 1983. 4. WATKINS, S.M. Using the design process to teach functional apparel design. Clothing and Textiles Research Journal, 1988, 7(1), 10-14. 5. DEEPATI, SINGH, S., GUPTA, R. Exploring characteristics of Indian handlooms for more sustainable fashion. In Proceedings of All India seminar on Diversity in Handlooms, Textiles, Global Trends in Fashion & Clothing, 9-12, 2019. Khairatabad : The Institution of Engineers, 2019. 6. WILSON, J. Handbook of textile designs principle, processes and practice. Cambridge : Woodhead Publishing, 2001. 7. ALOTHMAN, H., AKCAY, A. Fashion inspired by architecture: the interrelationship between Mashrabiya and fashion world. Journal of History Culture and Art Research, 2018, 7(2), 328-348, doi: 10.7596/taksad.v7i2.1480. 8. METE, F. The creative role of sources of inspiration in clothing design. International Journal of Clothing Science and Technology, 2006, 18(4), 278-293, doi: 10.1108/09556220610668509. 9. FARAHAT B.I. The interrelationship between fashion and architecture. Al-Azhar University Engineering Journal (JAUES), 2014, 9(6), 1-17. 10. STOKES, B., BLACK, C. Application of the functional, expressive and aesthetic consumer needs model: assessing the clothing needs of adolescent girls with disabilities. International Journal of Fashion Design, Technology and Education, 2012, 5(3), 179-186, doi: 10.1080/17543266.2012.700735. 11. DEVETAK, T. Space in fashion design - J2 (Fabiani Fashion) case study. South East European Journal of Architecture and Design, 2016, 1-6, doi: 10.3889/seejad.2016.10027. 12. MENON, V., SWETHA, R.G., KAUVERYBAI, S. Influence of mughal architecture on clothing. Journal of Farm Sciences, Special Issue, 2016, 29(5), 751-754. 194 Tekstilec, 2020, Vol. 63(3), 166-184 13. PAKSOY, H., YALÇ>N, S. Architectural inspirations in fashion design. In 3rd International Symposium of Interactive Media Design : conference proceedings, 2005, 1-9. 14. FISCHER, A. Basics fashion design 03: construction. Lausanne: AVA Publishing, 2009. 15. KUMARI, A. Elucidation of relationship between clothing silhouette and motifs with Indian Mughal architecture. Fashion and Textile, 2019, 6(17), 1-23, doi: 10.1186/s40691-019-0174-4. 16. TODOROVIC, Tijana, TOPORISIC,Tomaz, PAVKO CUDEN,Alenka. Clothes and costumes as form of nonverbal communication. Tekstilec, 2014, 57(4), 321-333, doi: 10.14502/ Tekstilec2014.57.321-333. 17. CHINWENDU, A.U. Architecture + fashion: a study of the connection between both worlds : M. Arch. Dissertation. Nottingham Trent University, 2014. 18. OZEZEN, N. Costume designs inspired by architecture. Project for Apparel Design Course. Adan : Çukurova University, Faculty of Fine Arts, Textile and Fashion Design Department, 2004. 19. QUINN, B. The fashion of architecture. Oxford: Berg Publisher, 2003. 20. GUPTA, D.D. Tourism marketing. New Delhi : Pearson Education, 2010. 21. GOVONI, N.A. Dictionary of marketing communications. Thousand Oaks : Sage Publications, 2004. 22. KOTLER, P. KELLER, K.L. Marketing management, 12th edition. Upper Saddle River, New Jersey: Pearsons/Prentice Hall, 2006, 654-655. 23. Hawa Mahal, Jainpur. Gulzar. Indian literature, 2009, 53(4; 252), 13, https://www.jstor.org/ stable/23340094. Tekstilec, 2020, Vol. 63(3), 195-202 | DQI:10.14502/Tekstilec2020.63.195-202 195 Kamrun Nahar1, Shurfun Nahar Arju2, Jannatul Ferdush1, Marzia Islam1, Tarifun Akter1 1 Northern University Bangladesh, Department of Textile Engineering, Kawlar Jamea Masjid Road 111/2, Dhaskhin Khan, Khilkhet, Dhaka 1229, Bangladesh 2 Bangladesh University of Textiles, Department of Wet Process Engineering, Shaheed Tajuddin Ahmed Avenue 92, Tejgaon Industrial Area, Dhaka 1208, Bangladesh Colorimetric Analysis and Fastness Properties of Jute Fabric Dyed with Eucalyptus Leaves Kolorimetrična analiza in obstojnost jutne tkanine, barvane z listi evkaliptusa Original scientific article/Izvirni znanstveni članek Received/Prispelo 3-2020 • Accepted/Sprejeto 6-2020 Corresponding author/Korespondenčna avtorica: Kamrun Nahar, senior lecturer E-mail: kamrun.butex@gamil.com Mobile: 8801731094445 Abstract Natural dyestuff has reverted its position in the colouration of textile substrates due to rising concerns of consumers and buyers, particularly about environmental impacts and health issues. Eucalyptus leaves were selected in this study as a source of natural dye along with some of the most generally used mordants to observe the impact of dyeing on jute fabric while trying to keep the dyeing parameters at a minimum level. Dyes were extracted from eucalyptus leaves by boiling in water. Then, the fabric was pre-mordanted using different synthetic mordanting agents, such as alum, potassium dichromate, copper sulphate and ferrous sulphate, which are generally used to substantively enhance the dyestuff on textile fabrics and to improve the fastness properties. Synthetic mordant was used here instead of natural mordant due to the better dyeing compatibility of jute fabric with eucalyptus leaves, since natural mordant has little effect on jute fabric during the process of dyeing. Another aim of this research is to curb the time and energy consumption of the jute dyeing process and so the dyeing is carried out at 75 °C for about 30 minutes. Various types of evaluations were conducted through visual assessment, checking the colour-coordinate values and colour strength values. While colour fastness properties were evaluated by different fastness testing, such as colour fastness to water, washing, rubbing and perspiration. This dyeing process yields a colour range from yellowish to brown with the variation of mordants applied on the fabric. In addition to that, colour co-ordinate and colour strength values ensure better results of dyed fabrics pretreated with ferrous sulphate. Jute fabric dyed with only extracted eucalyptus solution provided satisfactory results in all colour fastness tests, while fabric treated with different mordants showed variations in fastness ratings, and fabric treated with ferrous sulphate and copper sulphate had slightly better fastness ratings. Keywords: Colour-coordinate, colour fastness, eucalyptus leaves, jute fabric, mordant Izvleček Qdnos do naravnih barvil za barvanje tekstilij se je spremenil ob skrbi potrošnikov in kupcev za okolje in zdravje. V tej študiji so bili izbrani listi evkaliptusa kot vir naravnega barvila skupaj z nekaterimi najpogosteje uporabljenimi čimžami, da bi ugotovili vpliv barvanja na jutno tkanino ob ohranitvi parametrov barvanja na minimalni ravni. Barvila so bila ekstrahirana iz listov evkaliptusa pri vrenju v vodi. Nato je bila tkanina najprej čimžana v prisotnosti različnih sintetičnih čimž, kot so galun, kalijev dikromat, bakrov sulfat in železov sulfat, ki se po navadi uporabljajo za izboljšanje substantiv- 196 Tekstilec, 2020, Vol. 63(3), 166-184 nosti in obstojnosti barvila na tekstiliji. Namesto naravne čimže so bile zaradi boljše združljivosti barvanja jutne tkanine z listi evkaliptusa uporabljene sintetične čimže, ker naravne čimže med barvanjem v manjši meri vplivajo na jutno tkanino. Drugi cilj te raziskave je bil omejiti čas in porabo energije pri barvanju jute, tako da je barvanje potekalo približno 30 minut pri 75 °C. Opravljeni so bili različni načini ocenjevanja in sicer vizualno, preverjanje vrednosti barvnih koordinat in barvne jakosti. Barvna obstojnost je bila ocenjena z različnimi testiranji obstojnosti, kot je barvna obstojnost proti vodi, pranju, drgnjenju in znojenju. Ta postopek barvanja daje barvni razpon od rumenkaste do rjave barve glede na variiranje čimž, na-nesenih na tkanino. Poleg tega barvne koordinate in jakost barve zagotavljajo boljše rezultate obarvanja tkanine kot pri predhodno obdelanih z železovim sulfatom. Jutna tkanina, barvana samo z raztopino evkaliptusovega ekstrakta, daje zadovoljive rezultate barvne obstojnosti za vse barvne tone, medtem ko tkanine, obdelane z različnimi čimžami, kažejo razlike v ocenah obstojnosti in nekoliko boljšo oceno le za tkanine, obdelane z železovim sulfatom in bakrovim sulfatom. Ključne besede: barvna koordinata, barvna obstojnost, listi evkaliptusa, jutna tkanina, čimža 1 Introduction From ancient times onwards, colour from natural sources has been used enormously in various areas on a daily basis; for food, hair, medicine, furniture and even fabrics. Colour from different parts of plants or insects, in particularly bark, roots, leaves, stems, flowers and fruits [1], has been used extravagantly to dye natural fibres (i.e. wool, silk, cotton and jute). But to cope with the ever increasing demands for clothing, people have decreased the application of natural dye and switched to synthetic dyestuff as it is available and easy to apply, it exhibits moderate to good colour fastness, is economical. Environmental awareness raised questions on the use of huge amounts of salts and alkalis, which has detrimental effects on human life, and in return the usage of natural dyes as well as environment-friendly fabrics was revived [2-4]. Since such dyestuff is non-toxic, biodegradable and some types of dye also have special antimicrobial, UV protective and anti-flammable properties, it will be the buyers' and consumers' first requirement in the near future. Natural dyes, however, have low substantivity for textile substrates, and for this reason various mordanting agents are used before, during and after the dyeing process, what is known as pre-mordanting/simultaneously mordanting or post-mordanting process. Alum, potassium dichro-mate, copper sulphate, ferrous sulphate, vinegar, tin, etc. were used as mordant to intensify the colouring properties and colour fastness [5-9]. Natural mordants, such as aloe vera, mango bark, oak bark, chestnut wood, etc. are environmentally friendly and act as an effective mordanting agent for protein fabrics (e.g. silk and wool), but not for the jute fabric [10]. On the other hand, compatibility of mordanting agent with natural dyes depends on the chromophores in the dyestuff and the fabric, which the dye has to be applied on. Considering the aforementioned disadvantage of natural mordants, synthetic mordants were applied here to establish, which synthetic mordant is best suited for the dyeing of jute fabric with eucalyptus leaves. Eucalyptus leaves and bark are a substantial source of natural dyestuff that provides pale yellow to brownish colour [11]. About 10 to 12% of natural tannin and polyphenol in eucalyptus is responsible for the colouring of materials [12]. Quercetin is a major colouring component of eucalyptus bark and also an antioxidant, which is the reason for its utilisation in food colouring [13]. It is also used for colouration purposes of cotton fabrics [11, 14, 15]. Eucalyptus leaves contain up to 11% of tannin, gallic acid and ellagic acid - a pivotal part of phenolic acids and flavonoids, which enable the dyeing of natural fabrics, including wool and silk [16]. These two components are very useful in the dyeing process as they fix up the colour to the fabric. On the other hand, jute is a nearly 100% biodegradable fibre and is used for various purposes in textile sectors, including technical textiles. However, natural colouration of jute substrate is scarce and it is therefore mostly dyed with basic dyes. A study conducted by Rattanaphol Mongkholratta-nasit1, Jiri Krystufek, Jakub Wiener and Rattanaph-ol Mongkholrattanasit showed what happens when natural dye was extracted from eucalyptus leaves and applied to wool fabric. They extended their research on the impact of natural dye extracted from eucalyptus leaves on silk and wool fabrics using two padding techniques under different conditions, i.e. the pad-batch and pad-dry techniques [17]. In another study, Nattadon Rungruangkitkrai1, Rattanaphol Mongkholrattanasit, Wirat Wongphakdee and Jarmila Studnickova examined a dye extracted from eucalyptus leaves and its application to wool Colorimetric Analysis and Fastness Properties of Jute Fabric Dyed with Eucalyptus Leaves jg/ fabric using pad-batch and pad-dry techniques under various conditions. The fastness properties of dyed fabrics ranged from good to excellent, while light fastness fair to good. The fabric had an excellent value of ultraviolet protection factor (UPF). In addition, a darker colour was a result of FeSO,, which ' 4 provided better protection due to its higher UV absorption [18, 19]. It is known that dyes from eucalyptus leaves are mostly applied on protein or cotton fabrics, but its application on jute fabrics is very limited. In this study, a eucalyptus leaves extract is used to dye the jute fabric at an optimum temperature and time. Besides, it assesses which mordanting agent is more compatible for the dyeing of jute fabric with extracted eucalyptus leaves in respect of colour coordinates and colour fastness. 2 Materials and methods 2.1 Materials Substrate A plain woven grey jute fabric with mass per unit area 249 gm/m2 was used for dyeing. The fabric specifications were warp density 1.225 ends per meter, weft density 0.81 picks per meter and thickness 1.02 mm. Natural dyes Dye solutions were extracted from 20 g of eucalyptus leaves (i.e. Eucalyptus camaldulensis) that were collected in the Gazipur District. The leaves for extraction were gathered in November because during that time juvenile and adult leaves provide the most intense colour. Firstly, green eucalyptus leaves were chopped into small pieces and soaked in soft water (20 g of green leaves in 2000 ml of water) and thereafter boiled for one hour. Then, all the colouring matter was mixed with water with the help of heat and the dye solution was reduced to approximately 1000 ml. The maximum absorbency of this extracted dyestuff was obtained in the wavelength of 420 nm. Mordant Four types of mordant: alum, ferrous sulphate (FeSO4), potassium dichromate (K2Cr2O7) and copper sulphate (CuSO4) were used. All the mordants were 100% anhydrous, produced in the Northern University Textile lab, which was purchased from Mithila Chemicals Ltd. 2.2 Sample preparation The preparation of jute fabric for dyeing with eucalyptus leaves includes a pre-treatment process and a pre-mordanting process so that it can absorb natural dyestuff easily. As a result, four mordanting agents were used to pre-mordant the bleached jute fabric (Table 1). Bleaching of grey jute fabric Bleaching of the raw jute fabric was carried out in a closed vessel for one hour at 50-52 °C keeping the material at a liquor ratio 1:20 with hydrogen peroxide, trisodium phosphate (5 g/l), sodium hydroxide (1 g/l), sodium silicate (10 g/l) and non-ionic detergent (5 g/l). The pH of the bath was 11. After the fabric was washed thoroughly in cold water, it was neutralised with acetic acid (2 ml/l), washed in water again and then air dried. Mordanting of bleached jute fabric Bleached jute fabrics were pre-mordanted separately with alum, FeSO4, CuSO4, K2Cr2O7 at a similar concentration, i.e. 10% per weight of the fabric, at room temperature for about 24 hours, keeping the material at a liquor ratio 1:10. Then they were dyed without any washing. Dyeing of mordanted jute fabric with natural dye Jute fabrics that were pre-mordanted or not were dyed with the extracted dye solution from eucalyptus leaves at 75 °C for 30 minutes following the M:L = 1:20, which means that each of the 10 g jute fabric was dyed with 200 ml extracted dye solution at the above-mentioned dyeing parameters. Table 1: Designation of the dyed sample Sample designation Sample description S1 Bleached fabric without dyeing S2 Fabric dyed without mordant S3 Dyed fabric mordanted with alum S4 Dyed fabric mordanted with potassium dichromate S5 Dyed fabric mordanted with copper sulphate S6 Dyed fabric mordanted with ferrous sulphate 198 Tekstilec, 2020, Vol. 63(3), 166-184 2.3 Testing processes after dyeing Measurement of colour coordinate Using Datacolor® 850 Spectrophotometer the colour coordinate value of all dyed samples was measured by the CIE L*a*b* or the CIELCH method. CIE L*a*b* and CIELCH mean the following: L stands for lightness/darkness value, a* is red/green axis where +a represents redder and -a represents greener, b* is yellow/blue axis where +b represents yellower and -b bluer, C stands for chroma, +ve represents brighter and -ve represents duller, and H stands for hue. Measurement of colour strength The K/S value was assessed using the spectrophotometer to observe the colour strength of different reactive dyes, which works on the Kubelka-Munk equation 1: K = (1 -R)2 (1) 5 2 R where, R is the reflectance of dyed fibre. Evaluation of colour fastness to wash The ISO 105 C06 B2S method was applied to measure wash colour fastness properties of the dyed sample. In this method, a dyed fabric (10 cm x 4 cm) is attached to a TV multi fibre fabric and an undyed fabric like a sandwich and the sample was treated with an ECE reference detergent, sodium perborate tetra hydrate, acetic acid at 40 °C for 30 minutes in a washing machine where M:L was 1:50. Then, colour fastness to wash was assessed in respect to colour change (ISO 105 A02) and colour staining (ISO 105 A03) by matching with standard grey scales. Evaluation of colour fastness to water (ISO 105 E01) This test method evaluates the effect of water on fastness properties of a dyed fabric. First, each sample was cut to a size of 10 cm x 4 cm along the length or width. Then, the sample was paired with a TV multi-fibre fabric and soaked into water for a half an hour. All wet samples were then placed in a perspirome-ter in an oven to simulate exposure for three hours. Lastly, the colour change of the sample and the staining of the multifibre strip were evaluated. Assessment of wet and dry rubbing colour fastness (ISO 105-X12) Dyed samples of 14 cm x 5 cm were mounted on a crock meter and the finger of the crock meter covered with a 5 cm x 5 cm crocking cloth at the pressure of 9 ± 2 N. The samples were rubbed with the finger at 10 turns within 10 seconds. But for the wet rubbing test this process is followed after soaking the crocking cloth in water at a 100% pickup. Determination of perspiration fastness (ISO 105 E04) Colour fastness to perspiration of all dyed samples was measured in media like acid and alkali following the ISO 105 E04 testing method. Like the samples (10 cm x 4 cm) for the wash and water fastness, a multifibre fabric and undyed fabric were further soaked in an alkali and acid solution. Alkali and acid solutions were prepared by using 0.5 g/l l-histidine monohydrochloride monohydrate, 5 g/l sodium chloride, disodium hydrogen orthophosphate dehydrate/ sodium dihydrogen orthophosphate dehydrate and definite pH for acid and alkali. Testing samples had been dipped in this solution for about 30 minutes, then put in perspirometer at 37 °C for 4 hours in the oven. Then the samples were assessed. 3 Results and discussion 3.1 Visual appearance It was observed from the pictorial view of all dyed samples (Figure 1) that jute fabric, which was dyed with only extracted eucalyptus leaves, provides prominent colour, whereas jute fabric, which was pre-treated with different mordanting agents (e.g. alum, potassium dichromate and copper sulphate) does not. However, fabric dyed with ferrous sulphate yielded a dark ash colour. The probable reason of S2 yielding a brighter shade than S3 is the content of tannin and gallic acid in eucalyptus leaves, which has the capacity to colour the fabric without using mordanting agents. If alum was used as a mordanting agent, it reacted with dye molecules rather than enabling the fabric to absorb colour. On the other hand, ferrous sulphate intensifies the ability of tannin, gallic acid and quercetin to colour the fabric. 3.2 Colour coordinate value All of the dyed jute fabrics were assessed under two light sources, i.e. D65 - artificial day light and TL84 - store light, using two methods: CIE L*a*b* and CIELCH. It is shown in Table 2 that lightness of only bleached fabric is high, whereas it is decreased in fabrics dyed with eucalyptus leaves, pre-mordanted with ferrous sulphate for both light sources. The value of redness/blueness is highest (9.64) for dyed fabrics, Colorimetric Analysis and Fastness Properties of Jute Fabric Dyed with Eucalyptus Leaves jg/ S4 S5 S6 Figure 1: Pictorial view of dyed jute with eucalyptus leaves extract with and without mordant Table 2: Colour coordinate value of all samples dyed with eucalyptus (average values and their standard deviations are given in brackets) Sample D65 LT84 AE L a b C H L a b C H S1 60.71 (0.07) 4.92 (0.03) 16.89 (0.06) 17.59 (0.04) 73.77 (0.06) 61.72 (0.07) 4.97 (0.05) 19.17 (0.06) 19.80 (0.05) 75.48 (0.04) 2.49 S2 53.31 (0.03) 5.65 (0.02) 20.98 (0.05) 21.73 (0.03) 74.92 (0.06) 54.41 (0.04) 5.76 (0.05) 20.98 (0.05) 21.73 (0.03) 74.92 (0.07) 1.11 S3 57.26 (0.03) 5.94 (0.02) 20.44 (0.03) 21.29 (0.04) 73.80 (0.06) 58.41 (0.05) 6.00 (0.09) 23.17 (0.04) 23.93 (0.01) 75.48 (0.02) 2.96 S4 53.87 (0.04) 9.64 (0.02) 20.24 (0.02) 21.39 (0.07) 71.08 (0.05) 55.05 (0.09) 6.89 (0.06) 22.86 (0.06) 23.88 (0.06) 73.24 (0.03) 3.98 S5 51.12 (0.02) 6.71 (0.02) 24.04 (0.03) 24.96 (0.05) 74.41 (0.05) 52.45 (0.07) 6.56 (0.03) 27.24 (0.10) 28.02 (0.07) 76.45 (0.01) 3.47 S6 38.15 (0.02) 3.36 (0.02) 7.20 (0.02) 7.94 (0.03) 65.01 (0.04) 38.02 (0.04) 3.46 (0.03) 8.04 (0.04) 8.76 (0.03) 66.72 (0.03) 0.86 pre-mordanted with potassium dichromate. On the other hand, numerical value of b, C and H is higher for dyed fabric, pre-mordanted with ferrous sulphate. Moreover, it is clearly observed that the colour difference (0.86) of fabrics dyed with eucalyptus leaves and pre-mordanted with ferrous sulphate is lower than in all other dyed samples. 3.3 Evaluation of colour strength value A colour strength depends on reflectance. Higher value of reflectance is, greater is the value of colour strength. As a result, a dark sample has a high colour strength, and a light shade fabric has lower K/S value. In this regard, fabric dyed with ferrous sulphate gives colour strength in the range of 9 to 21, since it yields dark colour rather than other mordants. 3 ——,-,-,-,-, 450 500 550 600 650 700 Wave length (nm) -•- S1 S2 S3 S4 S5 -•- SG Figure 2: Colour strength value of each sample 200 Tekstilec, 2020, Vol. 63(3), 166-184 3.4 Colour fastness to water Fabric dyed with eucalyptus leaves yields outstanding water fastness. This was seen in all samples treated with or without mordants. The rating of colour fastness to water is 4 to 5 for both colour change and colour staining. 3.5 Colour fastness to wash Although there is no variation of colour, change in wash fastness is similar for all samples (4-5), however, in terms of colour staining, wash fastness is better (4-5) for samples dyed with extracted dye solution before they were treated with alum, as the colour is lighter than in other samples. Fabric pre-mordanted with potassium dichromate exhibits comparatively lower fastness rate after dyeing with eucalyptus leaves extraction. Figure 3 also shows that the error bar of samples due to wash fastness in respect of colour change is zero, while colour staining fastness provided a standard error of 0.187. 4,5 c !q ■Q 3 3,5 J3 3 c ■<5 2,5 in m 20000 12 0 Figure 2: (a) (b) dynamic 14 16 18 20 22 12 14 16 18 20 Solid content (%) Solid content (%) Solid content dependence of the areal weight of the PAN nanofibrous mats under investigation; viscosity of the corresponding spinning solutions the solution with 22% PAN. This could also be observed during the spinning process where nearly no flying fibres were observed in the spinning chamber. It should be mentioned that additional FFT investigations (not shown here) supported the optical impression that the fibres do not show any angular orientation, corresponding to the expectation for a nanofibre mat electrospun on a static, fully non-conductive substrate. Next, Figure 2a depicts the dependence of the areal weight on the solid content of the spinning solutions. While the curve increases sharply from 12% to 14% and almost linearly until 20%, it drops suddenly towards a solid content of 22%, as could already be expected from Figure 1. This is due to an increase in viscosity that exceeds the spinnability limit for the needleless spinning technique and no longer flows through the spinning nozzle properly. Viscosity values are given in Figure 2b for comparison. It should be mentioned that solutions with solid contents of 12-20% behaved nearly fully Newtonian in the measured range of rotational speeds, which is why the error bars are too small to be visible. Only for the spinning solution with 22% PAN, is a slight increase of the dynamic viscosity with increasing rotational speed visible, i.e. the fluid becomes shear-thickening. Combining both figures suggests that a solid content of 16-18% should be ideal for the wire-based electrospinning of PAN from DMSO, thus giving relatively high material yields while still allowing for the modification of the nanofibre diameter distribution. It should be mentioned that the conductivity of the solutions was in the range of 30-50 ^S/cm for all solutions, well below the maximum suggested conductivity of 10 mS/cm for the Nanospider, and thus can be expected to have no influence on the results of the spinning process. The nanofibre diameter distribution is depicted in more detail in Figure 3. For the lower concentrations of 12-16%, only a slight increase of the nanofibre diameter distribution is visible, with similar standard deviations, i.e. similar distribution widths. For a PAN content of 18%, as could already be seen in Figure 1, the diameter distribution is significantly shifted, while at the same time the standard deviation increases. Some fibres with larger diameters of around 750-1000 nm indicate that this PAN concentration is near to or slightly above the threshold below which a reliable fibre diameter distribution can be reached. This finding suggests further tests with solid contents of 17.0-17.5%, which could possibly lead to a compromise between the clearly differentiated, long, straight fibres prepared with an 18% PAN concentration and the narrower diameter distribution achieved with smaller concentrations. Finally, for concentrations of 20% and 22%, the distributions become very broad, with large standard deviations that are unacceptable for many applications, clearly showing that the highest areal weight, achieved with a concentration of 20%, comes at the cost of an undefined morphology of the nanofibrous mat. The chemical composition of the nanofibre mats under investigation can be derived from the FTIR graphs in Figure 4. The typical PAN peaks represent the bending and stretching vibrations of CH2 at 2938 cm-1, 1452 cm-1 and 1380 cm-1, stretching vibrations of the C=N nitrile functional group at 2240 cm-1, and the carbonyl (C=O) stretching peak at 1732 cm-1 [35]. Impact of Solid Content in the Electrospinning Solution on the Physical and Chemical Properties of Polyacrylonitrile (Pan) Nanofibrous Mats 229 200 400 600 800 Fibre diameter (nm) 1000 200 400 600 800 Fibre diameter (nm) 1000 200 400 600 800 Fibre diameter (nm) 1000 200 400 600 800 Fibre diameter (nm) 1000 200 400 600 800 Fibre diameter (nm) 1000 200 400 600 800 Fibre diameter (nm) 1000 Figure 3 contents ■ Fibre diameter distributions of nanofibrous mats, electrospun from solutions with different solid for 100 fibres each. Insets show averages ± standard deviations 0 0 0 0 0 0 The peaks not marked here in the ranges of 12501230 cm-1 and 1090-1030 cm-1 belong to C-O and C-O-C (ester) vibrations of co-monomers, such as itaconic acid or methyl acrylate, which are often added to PAN [35]. Around 2360-2320 cm-1, double-peaks are visible, which can sometimes be observed in FTIR measurements and are usually based on CO2 in gaseous and aqueous form [36], i.e. an artefact. Besides these undesired effects, all PAN peaks look identical in all samples, which could be expected as the composition of the solid content of the spinning solutions remained unaltered. Small deviations between the heights of the peaks can be attributed to thickness deviations and air inclusion in the thin nanofibre mats, in this way varying the overall signal. This shows that the chemical composition of the PAN nanofibre mats remains unaltered when the solid content in the solution is varied. 230 Tekstilec, 2020, Vol. 63(3), 166-184 Figure 4: FTIR (Fourier transform infrared spectroscopy)graphs of nanofibrous mats, electrospun with different PAN concentrations, given in weight percentage 4 Conclusion and outlook References Needleless electrospinning of PAN from DMSO can be performed for a broad range of solid contents in the solution. Our investigations reveal that concentrations of between 14% and 18% are ideal for most applications, resulting in high material yields and narrow fibre diameter distributions, while facilitating the tailoring of the diameter to a certain extent. Higher concentrations of 20% result unexpectedly in conglutinated fibres, which may be interesting for certain applications in which mechanical strength is more important than the high surface-to-volume ratio of the nanofibrous mats produced at lower concentrations. A solid content of 22% is no longer spinnable, while a PAN concentration of 12% also resulted in a low material yield. For all samples under examination, the chemical composition remained unaltered. Our study facilitates the identification of the optimum PAN concentrations for wire-based electro-spinning, which are quite different from the optimal values for the needle-based technique. Because PAN nanofibrous mats are often used as a precursor for carbon nanofibres, future investigations are necessary to examine the influence of the PAN concentration on the morphology and mechanical properties of carbonized nanofibrous mats, and on the carbon yield. 5. LI, Dan, XIA, Younan. Electrospinning of nanofibers : reinventing the wheel? Advanced Materials, 2004, 16(14), 1151-1170, doi: 10.1002/ adma.200400719. RENEKER, Darell H., CHUN, Iksoo. Nanometre diameter fibres of polymer, produced by electro-spinning. Nanotechnology, 1996, 7(3), 216-223, doi: 10.1088/0957-4484/7/3/009. MACOSSAY, Javier, MARRUFFO, Alexis, RINCON, Roman, EUBANKS, Tom, KUANG, Anxiu. Effect of needle diameter on nanofiber diameter and thermal properties of electro-spun poly(methyl methacrylate). Polymers for Advanced Technologies, 2007, 18(3), 180-183, doi: 10.1002/pat.844. SUN, Z., ZUSSMANN, E., YARIN, A. L., WENDORFF, J. H., GREINER, A. Compound core-shell polymer nanofibers by co-electro-spinning. Advanced Materials, 2003, 15(22), 1929-1932, doi: 10.1002/adma.200305136. HEKMATI, Amir Houshang, RASHIDI, Abosaeed, GHAZISAEIDI, Reza, DREAN, JeanYves. Effect of needle length, electrospinning distance, and solution concentration on morphological properties of polyamide-6 electrospun nanowebs. Textile Research Journal, 2013, 83(14), 1452-1466, doi: 10.1177/0040517512471746. 2 3 4 Impact of Solid Content in the Electrospinning Solution on the Physical and Chemical Properties of Polyacrylonitrile (Pan) Nanofibrous Mats 231 6. WANG, Xin, NIU, Haitao, WANG, Xungai. Needleless electrospinning of nanofibers with a conical wire coil. Polymer Engineering & Science, 2009, 49(8), 1582-1586, doi: 10.1002/pen.21377. 7. BANNER, Jana, DAUTZENBERG, Maria, FELDHANS, Theresa, HOFMANN, Julia, PLÜMER, Pia, EHRMANN, Andrea. Water resistance and morphology of electrospun gelatin blended with citric acid and coconut oil. Tekstilec, 2018, 61(2), 129-135, doi: 10.14502/ Tekstilec2018.61.129-135. 8. MAVER, Tina, KURECIC, Manja, PIVEC, Tanja, MAVER, Uros, GRADISNIK, Lidija, GASPARIC, Petra, KAKER, Barbara, BRATUSA, Ana, HRIBERNIK, Silvo, STANA KLEINSCHEK, Karin. Needleless electrospun carboxymethyl cellulose/polyethylene oxide mats with medicinal plant extracts for advanced wound care applications. Cellulose, 2020, 27(8), 4487-4508, doi: 10.1007/s10570-020-03079-9. 9. RENEKER, D. H., YARIN, A. L. Electros-pinning jets and polymer nanofibers. Polymer, 2008, 49(10), 2387-2425, doi: 10.1016/j. polymer.2008.02.002. 10. YARIN, A. L., KOOMBHONGSE, S., RENEKER, D. H. Taylor cone and jetting from liquid droplets in electrospinning of nanofibers. Journal of Applied Physics, 2001, 90(9), 4836-4846, doi: 10.1063/1.1408260. 11. MIT-UPPATHAM, C., NITHITANAKUL, M., SUPAPHOL, P. Ultrafine electrospun polyamide-6 fibers: effect of solution conditions on morphology and average fiber diameter. Macromolecular Chemistry and Physics, 2004, 205(17), 2327-2338, doi: 10.1002/ macp.200400225. 12. ZHANG, Jinning, SONG, Mingyu, LI, Dawei, YANG, Zhanping, CAO, Jianhua, CHEN, Yun, XU, Yang, WEI, Qufu. Preparation of self-clustering highly oriented nanofibers by needleless electrospinning methods. Fibers and Polymers, 2016, 17(9), 1414-1420, doi: 10.1007/s12221-016-6581-x. 13. LOMOS, S. V., MOLNAR, K. Compressibility of carbon fabrics with needleless electrospun PAN nanofibrous interleaves. Express Polymer Letters, 2016, 10(1), 25-35, doi: 10.3144/ expresspolymlett. 2016.4. 14. SABANTINA, Lilia, BOTTJER, Robin, WEHLAGE, Daria, GROTHE, Timo, KLOCKER, Michaela, GARCÍA MATEOS, José, RODRÍGUEZ-MIRASOL, José, CORDERO, Tomás, EHRMANN, Andrea. Morphological study of stabilization and carbonization of poly-acrylonitrile/TiO2 nanofiber mats. Journal of Engineered Fibers and Fabrics, 2019, 14, 1-8, doi: 10.1177/1558925019862242. 15. SEDGHI, Roya, SHAABANI, Alireza, SAYYARI, Nastaran. Electrospun triazole-based chitosan nanofibers as a novel scaffold for bone tissue repair and regeneration. Carbohydrate Polymers, 2020, 230, 1-12, doi: 10.1016/j.carbpol.2019.115707. 16. WORTMANN, Martin, FRESE, Natalie, SABANTINA, Lilia, PETKAU, Richard, KINZEL, Franziska, GÖLZHÄUSER, Armin, MORITZER, Elmar, HÜSGEN, Bruno, EHRMANN, Andrea. New polymers for needleless electrospinning from low-toxic solvents. Nanomaterials, 2018, 9(1), 1-11, doi: 10.3390/nano9010052. 17. MAVER, T., KURECIC, M., SMRKE, D. M., KLEINSCHEK, K. S., MAVER, U. Electrospun nanofibrous CMC/PEO as a part of an effective pain-relieving wound dressing. Journal of Sol-Gel Science and Technology, 2016, 79(3), 475-486, doi: 10.1007/s10971-015-3888-9. 18. SISAKOVA, K., ORINAK, A., ORINAKOVA, R., STRECKOVA, M., PATERA, J., WELLE, A., KOSTECKA, Z., GIRMAN, V. Methane decomposition over modified carbon fibers as effective catalysts for hydrogen production. Catalysis Letters, 2020, 150(3), 781-793, doi: 10.1007/ s10562-019-02962-w. 19. FOKIN, Nadine, GROTHE, Timo, MAMUN, Al, TRABELSI, Marah, KLÖCKER, Michaela, SABANTINA, Lilia, DÖPKE, Christoph, BLACHOWICZ, Tomasz, HÜTTEN, Andreas, EHRMANN, Andrea. Magnetic properties of electrospun magnetic nanofiber mats after stabilization and carbonization. Materials, 2020, 13(7), 1-11, doi: 10.3390/ma13071552. 20. BLACHOWICZ, Tomasz, EHRMANN, Andrea. Recent developments in electrospun ZnO nanofibers: A short review. Journal of Engineered Fibers and Fabrics, 2020, 15, 1-6, doi: 10.1177/1558925019899682. 21. ROCHE, Remi, YALCINKAYA, Fatma. Electrospun polyacrylonitrile nanofibrous membranes for point-of-use water and air cleaning. ChemistryOpen, 2019, 8(1), 97-103, doi: 10.1002/ open.201800267. 22. LEMMA, Solomon Mengistu, ESPOSITO, Alfonso, MASON, Marco, BRUSETTI, Lorenzo, CESCO, Stefano, SCAMPICCHIO, Matteo. 232 Tekstilec, 2020, Vol. 63(3), 166-184 Removal of bacteria and yeast in water and beer by nylon nanofibrous membranes. Journal of Food Engineering, 2015, 157, 1-6, doi: 10.1016/j. jfoodeng.2015.02.005. 23. BOYRAZ, Evren, YALCINKAYA, Fatma, HRUZA, Jaku, MARYSKA, Jiri. Surface-modified nanofibrous PVDF membranes for liquid separation technology. Materials, 2019, 12(17), 1-12, doi: 10.3390/ma12172702. 24. DALTON, Paul D., KLINKHAMMER, Kristina, SALBER, Jochen, KLEE, Doris, MÖLLER, Martin. Dirct in vitro electrospinning with polymer melts. Biomacromolecules, 2006, 7(3), 686-690, doi: 10.1021/bm050777q. 25. WEHLAGE, Daria, BLATTNER, Hannah, SABANTINA, Lilia, BÖTTJER, Robin, GROTHE, Timo, RATTENHOLL, Anke, GUDERMANN, Frank, LÜTKEMEYER, Dirk, EHRMANN, Andrea. Sterilization of PAN/gelatin nanofibrous mats for cell growth. Tekstilec, 2019, 62(2), 78-88, doi: 10.14502/Tekstilec2019.62.78-88. 26. WEHLAGE, Daria, BLATTNER, Hannah, MAMUN, Al, KUTZLI, Ines, DIESTELHORST, Elise, RATTENHOLL, Anke, GUDERMANN, Frank, LÜTKEMEYER, Dirk, EHRMANN, Andrea. Cell growth on electrospun nanofiber mats from polyacrylonitrile (PAN) blends. AIMS Bioengineering, 2020, 7, 43-54, doi: 10.3934/ bioeng.2020004. 27. LIN, Kun-Yi Andrew, YANG, Ming-Tong, LIN, Jyun-Ting, DU, Yunchen. Cobalt ferrite nano-particles supported on electrospun carbon fiber as a magnetic heterogeneous catalyst for activating peroxymonosulfate. Chemosphere, 2018, 208, 502-511, doi: 10.1016/j.chemosphere.2018.05.127. 28. GARCÍA-MATEOS, F. J., CORDERO-LANZAC, T., BERENGUER, R., MORALLÓN, E., CAZORLA-AMORÓS, D., RODRÍGUEZ-MIRASOL, J., CORDERO, T. Lignin-derived Pt supported carbon (submicron)fiber electro-catalysts for alcohol electro-oxidation. Applied Catalysis B: Environmental, 2017, 211, 18-30, doi: 10.1016/j.apcatb.2017.04.008. 29. BIAN, Ye, WANG, Shijie, ZHANG, Li, CHEN, Chun. Influence of fiber diameter, filter thickness, and packing density on PM2.5 removal efficiency of electrospun nanofiber air filters for indoor applications. Building and Environment, 2020, 170, 1-9, doi: 10.1016/j.buildenv.2019.106628. 30. NIKBAKHT, Mohammad, SALEHI, Majid, REZAYAT, Seyed Mahdi, MAJIDI, Reza Faridi. Various parameters in the preparation of chi-tosan/polyethylene oxide electrospun nanofibers containing Aloe vera extract for medical applications. Nanomedicine Journal, 2020, 7(1), 21-28, doi: 10.22038/nmj.2020.07.03. 31. BAZRAFSHAN, Zahra, STYLIOS, George K. Custom-built electrostatics and supplementary bonding in the design of reinforced Collagen-g-P (methyl methacrylate-co-ethyl acrylate)/ nylon 66 core-shell fibers. J. Mech. Behav. Biomed. Mater., 2018, 87, 19-29, doi: 10.1016/j.jmbbm.2018.07.002. 32. SABANTINA, Lilia, RODRÍGUEZ-MIRASOL, José, CORDERO, Tomás, FINSTERBUSCH, Karin, EHRMANN, Andrea. Investigation of needleless electrospun PAN nanofiber mats. AIP Conference Proceedings, 2018, 1952, 020085, doi: 10.1063/1.5032047. 33. WANG, Ran, LIU, Yang, LI, Brandon, HSIAO, Benjamin S., CHU, Benjamin. Electrospun nanofibrous membranes for high flux microfiltration. Journal of Membrane Science, 2012, 392-393, 167-174, doi: 10.1016/j.memsci.2011.12.019. 34. STORCK, Jan Lukas, GROTHE, Timo, MAMUN, Al, SABANTINA, Lilia, KLOCKER, Michaela, BLACHOWICZ, Tomasz, EHRMANN, Andrea. Orientation of electrospun magnetic nanofibers near conductive areas. Materials, 2019, 13(1), 1-14, doi: 10.3390/ma13010047. 35. MÓLNAR, Kolos, SZOLNOKI, Beáta, TOLDY, Andrea, VAS, László Mihály. Thermochemical stabilization and analysis of continuously electrospun nanofibers. J. Therm. Anal. Calorim., 2014, 117(3), 1123-1135, doi: 10.1007/ s10973-014-3880-6. 36. SCHÀDLE, Thomas, PEJCIC, Bobby, MIZAIKOFF, Boris. Monitoring dissolved carbon dioxide and methane in brine environments at high pressure using IR-ATR spectroscopy. Analytical Methods, 2016, 8(4), 756-762, doi: 10.1039/c5ay02744f. Tekstilec, 2020, Vol. 63(3), 233-238 | DOI: 10.14502/Tekstilec2020.63.233-238 233 Snezhina Angelova Andonova Faculty of Engineering, South-West University "Neofit Rilski", 66 Ivan Mihailov Str., 2700 Blagoevgrad, Bulgaria Influence of Fusing Conditions on the Change of Colour Shade in the Production of Clothing Vpliv pogojev fiksiranja na spremembo barvnega odtenka pri proizvodnji oblačil Original scientific article/Izvirni znanstveni članek Received/Prispelo 5-2020 • Accepted/Sprejeto 8-2020 Corresponding author/Korespondenčna avtorica: Assoc. Prof. Eng. Snezhina Andonova, PhD E-mail: andonova_sn@abv.bg ORCID: 0000-0003-0818-9947 Abstract One of the major technological processes in the sewing industry is the process of thermo-mechanical fusing (TMF). This is a process in which the main textile material connects to an additional textile material (interlining) through a polymer binder. This ensures better resistance to the shape of the individual parts of the sewing article. The main factors that influence the process are the temperature of the pressing plates, and the pressure and the duration of the process. The process has not been sufficiently studied and therefore it is important to identify a function that connects the output parameter to the input factors of the TMF process. It is especially important to choose an optimisation criterion. After numerous preliminary studies, some changes in textile materials (TM) after TMF have been observed. For example, the incorrect adjustment of process parameters (e.g. pressure, temperature and duration) changes the colour shade of TM after TMF. This change in the colour shade of the individual parts will impair the quality of the sewing product as a whole. This encourages the selection of the quality criterion. In light of the latter, the purpose of this paper was to derive a mathematical model of the TMF process that describes the influence of input factors on the quality criterion: changing the colour shade of TM after TMF. Keywords: thermo-mechanical fusing process, change of colour shade Izvleček Eden glavnih tehnoloških procesov v konfekcijski industriji je termomehanski postopek fiksiranja. To je postopek, pri katerem se osnovni tekstilni material poveže z dodatnim tekstilnim materialom (medvlogo) s polimernim lepilnim termoplastom. S tem se poveča obstojnost oblike posameznih delov šivanega izdelka. Glavni dejavniki, ki vplivajo na postopek, so temperatura stiskalnih plošč, tlak in časovni potek postopka. Sam postopek fiksiranja še ni bil v celoti raziskan z vidika funkcijske odvisnosti med vhodnimi dejavniki termomehanskega taljenja z izhodnimi parametri. Še zlasti je pomembna možnost izbire optimalnih kriterijev. Po številnih predhodnih študijah so bile opažene nekatere spremembe tekstilnih materialov po termomehanskem taljenju. Na primer, nepravilna nastavitev parametrov (tlaka, temperature in časa) spremeni barvni odtenek tekstilnega materiala po fiksiranju. Takšna sprememba barvnega odtenka posameznih oblačilnih delov poslabša kakovost oblačila kot celote. To narekuje pravilno izbiro kriterijev kakovosti, zato je v članku izpeljan matematični model termomehanskega fiksiranja, ki opisuje vpliv vhodnih dejavnikov na enega od kriterijev kakovosti - spreminjanje barvnega odtenka tekstilnega materiala končnega izdelka. Ključne besede: termomehanski postopek fiksiranja, sprememba barvnega odtenka 234 Tekstilec, 2020, Vol. 63(3), 166-184 1 Introduction One of the major technological processes in the sewing industry is the process of thermo-mechanical fusing (TMF). This is a process in which the main textile material connects to an additional textile material (interlining) through a polymer binder. This ensures better resistance to the shape of the individual parts of the sewing article. The main factors that influence the process are the temperature of the pressing plates, and the pressure and the duration of the process. From the study conducted, it can be summarised that some investigations were made to determine the effect of individual parameters on the TMF process [1-4]. However, the combined influence of controllable factors, for example to satisfy the quality and performance criteria, has not been sufficiently studied. Globally, many elite companies have conducted research in this area, but their studies are commercial or confidential. In this context, it is necessary to derive a mathematical model of the TMF process through research and analysis with the help of modern control and measuring equipment. It is especially important to choose an optimisation criterion. Optimisation criteria (i.e. output parameters) can be quality criteria or performance criteria. In industrial technology, time is often used as a criterion for productivity [5-8]. In one study [9], a mathematical model of the TMF process was created to describe the relationship between the duration of the process and input factors. In any scientific study, it is especially important to define an effective quality criterion, as well. Quality assurance and quality control represent a complex area of the apparel industry. Quality assurance is not quality control, but quality control is an aspect of quality assurance. Quality assurance builds quality into each step of the manufacturing process [10]. Therefore, it is especially important to study the influence of TMF conditions on the quality of the sewing product [11]. From the literature review, it can be concluded that this issue has not been sufficiently investigated. After numerous preliminary studies, some changes in textile materials (TM) after TMF have been observed. For example, the incorrect adjustment of process parameters (e.g. pressure and temperature) changes the colour shade of TM after TMF. For some technological processes, colour change is a desired effect. It is especially fashionable to generate faded effects on indigo dyed denim fabric [12]. For the TMF technological process, however, the change of the colour shade of the main textile materials is an entirely undesirable effect. The change in the colour shade of individual parts will impair the quality of the sewing product as a whole. This encourages the selection of the quality criterion. In this work, the colour change after TMF is used as a quality criterion. The conditions for carrying out the TMF process are also especially important. In recent years, the sewing industry has used an increasing number of new and different textile materials. Each of them has a different composition and structure. It is rare to find two fibres or textile materials at random that exhibit the same characteristics [13]. This determines their different properties [5, 9, 14, 15]. In light of the latter, it is important to choose a manageable factor that is related to the type and structure of the studied textile materials. One study [16] illustrates the relationship between the mass per unit area, the composition and the structure of the respective type of textile material. The purpose of this paper was to derive a mathematical model of the TMF process that describes the influence of the input factors (e.g. pressure, the temperature of the pressing plates and the mass per unit area of basic textile materials) on the quality criterion: changing the colour shade of TM after TMF. 2 Experimental work When carrying out experimental work it is important to take into account the reflective properties of the TM. These properties depend on many factors. They include colour, dye concentration, composition and structure of TM and many others. For this reason, TMs of the same colour are used in the experiment. On the other hand, this ensures the reproducibility of the process. 2.1 Methods In formulating the conditions and methods for conducting the experiment, the principles of the morphological method for analysis and synthesis of methods were applied [17]. It is important to determine the method for quantifying the change in colour shade of TM after TMF. This quantification in the present work was carried out using a modern objective method. The DATA COLOR measurement system was used for colour measurement. That system comprises a spectrophotometer and a computer. Influence of Fusing Conditions on the Change of Colour Shade in the Production of Clothing 235 The device used was highly sensitive. The method was carried out over a short time frame, with a sufficient degree of accuracy. It is reproducible, versatile and affordable. The studies were performed with monochromatic TMs, coloured in black. The full factorial experiment (FFE) method was used to create a mathematical model. It implements all possible combinations of two levels of factors. The number of these combinations for n factors is N = 2n [5, 18]. The basic elements for the compilation of the mathematical model were determined using the methodology for the implementation of FFE [5, 18]. 2.2 Conditions for conducting the experiment In order to determine the conditions for conducting the experiment, it was also necessary to select manageable factors. The following were selected for controllable (manageable) factors: X1 representing the pressure of the pressing plate, P (N/cm2); X2 representing the temperature of the pressing plates, T (°C); and X3 representing the mass per unit area of basic textile materials, M (g/m2). The main factor levels and intervals of variation are given in Table 1 [9]. The temperature between the basic TM and the auxiliary TM (interlining) was TM (material temperature). After conducting a number of preliminary studies, the following conditions for conducting the experiments were selected: • an ATLAS - I. BALA - 4-93 fusing machine (stationary press type "drawer"); and • the TM temperature (TM) was recorded with a computer integrated measurement system [19]. The temperature (TQ) is assumed to be the temperature required for quality bonding when working with the textile materials described. The fusing process was finalised when TM reached TQ [4]. After numerous preliminary experiments, it was found that TQ = 112 °C for the studied TM. 2.3 Materials Materials produced by the company NITEX-50 (Sofia) were used for basic textile materials. They were 100% wool fabrics: article EKSELSIOR with a mass per unit area 173 g/m2, warp threads density of 122 pcs/10 cm and weft threads density of 230 pcs/10 cm; article RITZ with a mass per unit area of 193 g/m2, warp threads density of 175 pcs/10 cm and weft threads density of 263 pcs/10 cm; and article KARDINAL with a mass per unit area 213 g/ m2, warp threads density of 370 pcs/10 cm and weft threads density of 232 pcs/10 cm [9]. Material produced by the company Kufner-B121N77 was used for interlining textile material (auxiliary textile material). The interlining TM is tissue with a mass per unit area of 63 g/m2, warp threads of 100% PES and weft threads of 100% PES. 3 Results and discussions 3.1 Experimental results The design of the experiment is given in Table 2. The number of factor levels is k = 2; the number of factors is n = 3 (I, l and p representing the sequences numbers of factors), therefore [5, 18] N = 8. 3.2 Discussion of experimental results It is necessary to carry out a process reproducibility check, which is reduced [5, 18] to a variance perseverance check (using Cochran's C test). The results for the calculated and tabulated value of the Cochran's C test are: S2 GC = jL = 0125 Xs 2 j=i GT[f% = m - 1; f2 = n; r = 0,05} = 0,6798 (1) (2) where: "r" represents the significance level and "f1" and "f2" represent degrees of freedom. Table 1: Factor levels Factors levels Xj - P (N/cm2) X2 - T (°C) X3 - M (g/m2) Natural Coded Natural Coded Natural Coded X. + J. 40 + 1 150 + 1 213 + 1 X . 01 25 0 135 0 193 0 X. - J. 10 - 1 120 - 1 173 - 1 J. 15 15 20 236 Tekstilec, 2020, Vol. 63(3), 166-184 Table 2: Design of the experiment Ne Xo X1 X2 X3 X1X2 X1X3 X2X3 X1X2X3 Y je 1 + - — — + + + - 0.5 0.4925 2 + + — — - - + + 1.2 1.2075 3 + - + - - + - + 1.07 1.0625 4 + + + - + - - - 1.63 1.6375 5 + - - + + - - + 0.91 0.9175 6 + + - + - + - - 1.57 1.5625 7 + - + + - - + - 1.25 1.2575 8 + + + + + + + + 1.91 1.9025 The number of repetitions of the jth test (j = 1+N) is m = 2. The results of the experiments (Y) are also given in Table 2. Therefore, the intra-group variance does not differ statistically and the process is reproducible. Regression coefficients were determined using formulas (3) to (12) [5, 18]: N = 1,255 (=i 1 * bi=N&XiiVi 7 = 1 b" = 0,3225 b2 = 0,21 b3 = 0,155 + )=I + >=^'X1JX2JYJ = (-0,0175 b"# = 0,0075 b23 = (-0,04) blip = ¿123 (3) (4) (5) (6) (7) (8) (9) (10) (11) N = 1+Xi-*2-*3-ÏÔ = 0,0175 (12) -=i The output parameter variance was defined according to (13) [5, 18]: m (13) The variance of reproducibility was determined according to (14) [5, 18]: N 1 = 1 0002 (14) The variances of the regression coefficients were determined according to (15) [5, 18]: S2 S(Bi) = ^ = 0,000025 N(m - 1) (15) The significance of the calculated regression coefficients was verified. Student's t-test was used. Only those coefficients were significant for which the following was valid [5, 18]: tc > tT, (16) where: tC represents the calculated coefficient; tT represents the table value of Student's t-test, with the selected significance level of r = 0,05 and the degree of freedom of f = N (m-1) = 8. The value of Student's t-distribution was defined as: tT = 2.31. tC was determined according to (17) [5, 18]: m S(B*) (17) Therefore: ^ = 251; ^ = 64.5; tc(b2) = 42* tc(b3) = 31* t — 3 5* t — 15* t — 8* t — 35 C(b12) ' C(b13) C(b23) ' LC(b123) _ Influence of Fusing Conditions on the Change of Colour Shade in the Production of Clothing 237 The only insignificant coefficient was b13, the absolute value of which was smaller than the critical value. After eliminating the insignificant coefficient, the model took the following form: Yc = 1,255 + 0,3225 • x1 + 0,21 • x2 + 0,155 •xs- 0,0175 •x1^x2 (18) - 0,04 • x2 • x3 + 0,0175 • x1 • x2 • x3 Verification of model adequacy: • the adequacy variance was established (19) [5, 18]: N m v—i _ _ Slo. = J)(yi - Yic)2 = 0,0009 (19) J i=i where: f = N-M=1, Y represents the value calculated by the mathematical model (Table 2) and M represents the number of significant regression coefficients. • the expected Fisher's F-test was calculated according to (20) [18]: Fc=S-k& = 4,5 (20) ■V) • the table value of Fisher's distribution was: Ft {r = 0.05; f = N-M = 1; f2 = N(m-1) = 8} = = 5.32 [5, 18]. As FC = 4.5 < 5.32= FT, the model is adequate [5, 18]. Therefore, the hypothesis that a mathematical model of the type (18) is adequate can be accepted with a confidence probability of P = 0.95. 4 Conclusion After a thorough analysis of the nature and characteristics of the technological TMF process of a stationary press type "drawer", a full factorial experiment was planned to make a mathematical model of the process. The change in the colour shade of the sewing parts after TMF was selected as a quality criterion. A mathematical model of the TMF process was created for the corresponding experimental conditions. It showed how the output quality parameter is linked to the input factors, i.e. the pressure P (N/cm2), temperature T (°C) and mass per unit area of basic textile materials M (g/m2). The conducted research has an applied-scientific character. The mathematical model obtained creates the conditions for quickly finding another combina- tion of inputs that satisfies the quality criterion. This helps to quickly solve real production problems and optimise the process. References 1. ANDONOVA, Snezhina. Analysis of factors influencing the process of thermomechani-cal sticking in the sewing industry. Journal of Multidisciplinary Engineering Science and Technology, 2019, 6(10), 10884-10887. 2. PETROV, H. Research on the creation of high-performance technologies and equipment for the sticking of textiles: dissertation. Sofia : University Press: 1991. 3. MOTEJL, V. Machines and equipment in clothing production. Praha : SNTL, 1984. 4. ANDONOVA, S., STEFANOV, A., AMUDZHEV, 1. An investigation of the thermo-mechanical fusing process of innovative textile material. Industria Textila Journal (in press). 5. DAMYANOV, G., GERMANOVA-KRASTEVA, D. Textile processes: quality control and design of experiments. New York : Momentum Press, 2012. 6. AMUDJEV, Ivan, KRUMOV, K., KUZMANOV, V. Modelling of the micro hardness obtained in the burnishing process by means of adding rotations around crossing axes. Journal Mechanical Engineering and Machine Science, 2011, 13(1), 64-68. 7. NEDYALKOV, Ivan, STEFANOV, Aleksej, GEORGIEV, Georgi. Modelling and studying of cloud infrastructures. In 2018 International Conference on High Technology for Sustainable Development (HiTech), Sofia, 2018, 1-4, doi: 10.1109/HiTech.2018.8566664. 8. COLOVIC, G. 3 - Determining time of technological operations in clothing production. Management of Technology Systems in Garment Industry, 2011, 43-79, doi: 10.1533/9780857094049.43 9. ANDONOVA, Snezhina Angelova. Mathematical modeling of the thermo-mechanical fusing process. Vlákna a tekstil (Fibres and Textiles), 2020, 2, 3-7. 10. KEIST, C. 16 - Quality control and quality assurance in the apparel industry. In Garment Manufacturing Technology. Woodhead Publishing Series in Textiles. Elsevier, 2015, 405-426, doi: 10.1016/B978-1-78242-232-7.00016-3. 238 Tekstilec, 2020, Vol. 63(3), 166-184 11. GRIES, T., LUTZ, V., NIEBEL, V., SAGGIOMO, M., SIMONIS, K. 14 - Automation in quality monitoring of fabrics and garment seams. In Automation in Garment Manufacturing, The Textile Institute Book Series. Elsevier, 2018, 353376, doi: 10.1016/B978-0-08-101211-6.00014-8. 12. VENKATRAMAN, Prabhuraj, LIAUW, Christopher. Use of a carbon dioxide laser for environmentally beneficial generation of distressed/ faded effects on indigo dyed denim fabric : evaluation of colour change, fibre morphology, degradation and textile properties. Optics & Laser Technology, 2019, 111, 701-713, doi: 10.1016/j. optlastec.2018.09.004. 13. HOUCK, Max, SIEGEL, Jay. Chapter 15 -Textile fibers. In Fundamentals of forensic science. Elsevier, 2015, 381-404, doi: 10.1016/ B978-0-12-800037-3.00015-7. 14. RAHNEV, I. Mechanics of the textile threads. International Journal of Clothing Science and Technology, 2005, 17(6), 39-40. 15. MANUSOV, V., MATRENIN, P., KHASANZODA, N. Swarm algorithms in dy- namic optimization problem of reactive power compensation units control. IJECE, 2019, 9(5), 3967-3974, doi: 10.11591/ijece.v9i5.pp3967-3974. 16. ANDONOVA, Snezhina Angelova, GAETANO, Rimini. Analysis and practical criteria for assessing the uniformity of fabric mass per unit area. Vlakna a tekstil (Fibres and Textiles), 2020, 2, 13-17. 17. AMUDJEV, I. Applying of the morphological method for analysis and synthesis of methods for finishing of external cylindrical surfaces by means of surface plastic deformation. Journal of Technical University of Gabrovo, 2007, 34, 19-25. 18. DAMYANOV, G. Textile processes: mathematical methods for the planning of an experiment in the research in the textile industry. Sofia : IOT, 1977. 19. TRIFONOV, Kiril, ANDONOVA, Snezhina, GEBOV, Vladimir. Computer-integrated system for measuring the temperature during pressing. Tekstil i Obleklo, 2005, 11, 18-21. SHORT INSTRUCTIONS FOR AUTHORS OF SCIENTIFIC ARTICLES Scientific articles categories: Original scientific article is the first publication of original research results in such a form that the research can be repeated and conclusions verified. Scientific information must be demonstrated in such a way that the results are obtained with the same accuracy or within the limits of experimental errors as stated by the author, and that the accuracy of analyses the results are based on can be verified. An original scientific article is designed according to the IM RAD scheme (Introduction, Methods, Results and Discussion) for experimental research or in a descriptive way for descriptive scientific fields, where observations are given in a simple chronological order. - Review article presents an overview of most recent works in a specific field with the purpose of summarizing, analysing, evaluating or synthesizing information that has already been published. This type of article brings new syntheses, new ideas and theories, and even new scientific examples. No scheme is prescribed for review article. - Short scientific article is original scientific article where some elements of the IMRAD scheme have been omitted. It is a short report about finished original scientific work or work which is still in progress. Letters to the editor of scientific journals and short scientific notes are included in this category as well. Language: The manuscript of submitted articles should be written in UK English and it is the authors responsibility to ensure the quality of the language. Manuscript length: The manuscript should not exceed 30,000 characters without spacing. Article submission: The texts should be submitted only in their electronic form in the format *.doc (or *docx) and in the format *.pdf (made in the computer program Adobe Acrobat) to the address: tekstilec@a.ntf.uni-lj.si. The name of the document should contain the date (year-month-day) and the surname of the corresponding author, e.g. 20140125Novak.docx. The articles proposed for a review need to have their figures and tables included in the text.The article can also be submitted through a cloud-based file transfer service, e.g."WeTransfer" (www.wetransfer.com). Publication requirements: All submitted articles are professionally, terminologically and editorially reviewed in accordance with the general professional and journalistic standards of the journal Tekstilec. Articles are reviewed by one or more reviewers and are accepted for publication on the basis of a positive review. If reviewers are not unanimous, the editorial board decides on further proceedings.The authors can propose to the editorial board the names of reviewers, whereas the editorial board then accepts or rejects the proposal. The reviewers'comments are sent to authors for them to complete and correct their manuscripts. The author is held fully responsible for the content of their work. Before the author sends their work for publication, they need to settle the issue on the content publication in line with the rules of the business or institution, respectively, they work at. When submitting the article, the authors have to fill in and sign the Copyright Statement (www. tekstilec.si), and send a copy to the editors by e-mail. They should keep the original for their own personal reference. The author commits themselves in the Copyright Statement that the manuscript they are submitting for publication in Tekstilec was not sent to any other journal for publication. When the work is going to be published depends on whether the manuscript meets the publication requirements and on the time reference the author is going to return the required changes or corrections to the editors. Copyright corrections: The editors are going to send computer printouts for proofreading and correcting. It is the author's responsibility to proofread the article and send corrections as soon as possible. However, no greater changes or amendments to the text are allowed at this point. Colour print: Colour print is performed only when this is necessary from the viewpoint of information comprehension, and upon agreement with the author and the editorial board. More information on: www.tekstilec.si