Indian Journal of Fibre & Textile Research

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VOLUME 32

NUMBER 1

 MARCH 2007

CODEN : IJFRET

 

ISSN : 0971-0426

 

CONTENTS

 

Creep behaviour of braided cordages made of high performance fibres for aerospace applications

         S K Pal, Vikas B Thakare & Gaurav Singh

        [IPC Code: Int. Cl.8 D01D5/00]

 

 

13

Analysis of structural effects formation in fancy yarn

        Salvinija Petrolatum

        [IPC Code: Int. Cl.8 D02G1/00]

 

21

Structural and mechanical characteristics of polyester dref-3 yarns in relation to fibre profile and annealing treatment

        G K Tyagi, Kaushal Raj & J Singh

        [IPC Code: Int. Cl.8 D02G3/00]

 

 

27

Study on fibre migration at different yarn layers

        M Murugesan & Ramesh Chandran Nayar

        [IPC Code: Int. Cl.8 D02G3/00]

 

33

Weavability of core-spun dref yarns

        B K Behera & V K Joshi

        [IPC Code: Int. Cl.8 D02G3/00, D03D]

 

40

Effect of some nozzle parameters on the characteristics of jet ring-spun yarns

        S N Subramanian, A Venkatachalam & V Subramaniam

        [IPC Code: Int. Cl.8 D02G3/00]

 

47

Effect of chitosan treatment on the properties of turmeric dyed cotton yarn

        T Kavitha, R Padmashwini, A Swarna, V R Giri Dev, R Neelakandan &
M Senthil Kumar

        [IPC Code: Int. Cl.8 A61F5/00, D02G3/00, D06P1/00]

 

53

Effect of mass of seed cotton and its lint quality on yarn properties

        N M Imayathamizhan, K Raghunathan & M R Srikrishnan

        [IPC Code: Int. Cl.8 D02G3/00]

 

57

Geometrical modelling of plain weft knitted fabrics

        Savvas G Vassiliadis, Argyro E Kallivretaki & Christopher G Provatidis

        [IPC Code: Int. Cl.8 D04B1/00]

62

Comfort properties of non-conventional light weight worsted suiting fabrics

        B K Behera & Rajesh Mishra

        [IPC Code: Int. Cl.8 D03D]

 

72

Static and kinetic frictional characteristics of staple fibres and woven fabrics

        A Das & S M Ishtiaque

        [IPC Code: Int. Cl.8 D03D, G01N33/36]

 

80

Antimicrobial activity of cotton fabric treated with Quercus infectoria extract

        Deepti Gupta & Ankur Laha

        [IPC Code: Int. Cl.8 A61K9/70, D06M13/00]

 

88

Wetting behaviour of raw and water-repellent cotton fabrics using wetting kinetic measurements

        M Mazloompour, N Ansari & N Hemmatinejad

        [IPC Code: Int. Cl.8 D06B3/00, D06C]

 

 

93

Imparting antimicrobial and fragrance finish on cotton using chitosan with silicon softener

        Anjali Karolia & Snehal Mendapara

        [IPC Code: Int. Cl.8 A61K9/70, D06M13/00]

 

99

Synthesis and characterization of aqueous UV-curable binder for ink preparation in ink-jet printing and pigment dyeing of fabrics

        M M El-Molla

        [IPC Code: Int. Cl.8 D06P5/30]

 

 

105

Use of triclosan as antibacterial agent in textiles

        Mehmet Orhan, Dilek Kut & Cem Gunesoglu

        [IPC Code: Int. Cl.8 D06B3/00]

 

114

Short Communications

 

 

Application of poly (lactic acid) fibres in automotive interior

        Subhas Ghosh & Sukanya Krishnan

        [IPC Code: Int. Cl.8 D01B]

 

119

Antimicrobial activity of cotton fabric pretreated by microwave plasma and dyed with onion skin and onion pulp extractions

        Chonyu Chen & Wen-Ya Chang

        [IPC Code: Int. Cl.8 A61K9/70, D06M13/00, D06P3/00]

 

 

122

Review Article

 

 

Parameters involved in assessment of dry state colour of fabrics from their wet state colour

        M Senthilkumar & N Selvakumar

        [IPC Code: Int. Cl.8 D06P5/00]

126

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 13-20

 

Creep behaviour of braided cordages made of high performance fibres for aerospace applications

S K Pal, Vikas B Thakare & Gaurav Singh

Revised received 2 January 2006; accepted 9 March 2006

The creep behaviour of braided cordages made of different high performance fibres, such as ultra high molecular weight extended chain polyethylene (Spectra® and Dyneema®), liquid crystalline polymer (Vectran®) and high tenacity nylon has been studied and then compared both during loading and relaxation phases. Nylon and Vectran® appear to have superior creep behaviour to that of Dyneema® and Spectra®. The heat setting has been found to improve the creep behaviour of nylon cordages.

Keywords: Braided cordage, Creep, Dyneema®, Heat setting, Nylon-66, Spectra®, UHMWECPE, Vectran®

IPC Code: Int. Cl.8 D01D5/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 21-26

 

 

Analysis of structural effects formation in fancy yarn

 

Salvinija Petrulyte

Revised received 2 January 2006; accepted 3 March 2006

The fancy effects formation using one process and hollow spindles has been studied. A composite design has been formulated and three variables, namely delivery speed of fancy yarn, rotational speed of hollow spindle and supply speed of effect component, considered to understand how technological parameters influence the formation of fancy effects, like closed loop, opened loop, loop-knot, plain knot and knot made from various loops, and their combinations. Procedure of counting the effects per unit length using twist tester and stereomicroscope for precise establishment of fancy effect is also accomplished. It is observed that the technological parameters contribute significantly to structural effects formation. On the basis of graphical pictures of the mathematical model that express the relationship between the number of effects of plain knot-knot made of various loops per unit length of fancy yarn and all the parameters of technological process of production, the particular interrelations have been investigated and the received model could be used to predict the number of fancy effects of certain nature, to control the effect formation process, and to enlarge the base of information needful for yarn design.

Keywords: Cotton, Fancy yarn, Hollow spindle technology, Knot

IPC Code: Int. Cl.8 D02G1/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 27-32

 

Structural and mechanical characteristics of polyester dref-3 yarns in relation to fibre profile and annealing treatment

 

G K Tyagi, Kaushal Raj & J Singh

Received 19 December 2005; revised received and accepted 10 March 2006

The influence of process parameters and annealing treatment on structural parameters, tensile properties, flexural rigidity and abrasion resistance of polyester dref-3 yarns has been studied. Annealing leads to a marked increase in helix angle and helix diameter, and a decrease in mean fibre extent. The results show significant improvement in breaking extension, work of rupture and abrasion resistance, and an appreciable decrease in tenacity, hairiness and flexural rigidity on annealing. The degree of change in these characteristics is more marked in the yarns made from a circular polyester fibre and the coarse fibre denier, thicker core and higher production speed facilitate it. Compared to the yarns made from a trilobal fibre, the yarns spun from a circular fibre exhibit higher thermal shrinkage which further increases with the increase in spinning speed.

Keywords: Annealing, Core-wrapper ratio, Dref-3 yarn, Polyester yarn, Thermal shrinkage, Trilobal fibre

IPC Code: Int. Cl.8 D02G3/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 33-39

 

 

 

Study on fibre migration at different yarn layers

M Murugesan & Ramesh Chandran Nayar

Received 23 August 2005; accepted 24 March 2006

The magnitude of deviations (root mean square deviation) from the mean radial position of the fibre has been studied in various yarns by using tracer fibre technique. Three sets of yarns with tracer fibre have been prepared, considering different break drafts, yarn twists and traveller weights. The effect of yarn tension and twist due to position of ring rail (balloon height) and yarn package diameter has been nullified by taking samples from the various cops at the same height and yarn package diameter. The results of root mean square deviation of tracer fibres have been categorized with respect to the span length and their mean radial position and then analysed. It is observed that the increase in traveller weight causes an appreciable decrease in root mean square deviation and has no significant effect on the mean radial position of the fibre. Similarly, the increase in yarn twist causes an increase in root mean square deviation and decrease in mean radial position. The increase in break draft enhances the root mean square deviation initially and then causes it to decrease while the mean radial position increases steadily with the increase in break draft. Migration study has also been carried out in the yarn present at the bare of the cop and surface of the cop. Root mean square deviation of yarn measured at bare of the cop is less as compared to that of the yarn present at the surface of cop.

Keywords: Break draft, Fibre span length, Mean radial position, Root mean square deviation, Tracer fibre, Traveller weight,   Twist

IPC Code: Int. Cl.8 D02G3/00

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 40-46

Weavability of core-spun dref yarns

B K Behera  & V K Joshi

Revised received 25 October 2005; accepted 13 December 2005

A new method for evaluating weavability of heterogeneous core-spun dref yarns has been suggested. Among core-spun dref yarns, the weaving performance of cotton core dref yarn is found to be superior followed by that of dref yarns with textured core,  Z-twist core and S-twist core. Under identical conditions, sizing causes deterioration in weaving performance of dref yarns, except in case of 100% cotton dref yarn.

Keywords : Core-spun yarn, Dref yarn,  Sizing, Textured yarn, Weavability

IPC Code: Intl Cl.8 D02G3/00, D03D

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 47-52

 

Effect of some nozzle parameters on the characteristics of jet ring-spun yarns

 

S N Subramanian, A Venkatachalam & V Subramaniam

Revised received 14 December 2005; accepted 24 February 2006

The effect of single, double and triple air-jet nozzles of different materials, such as brass, aluminium and teflon, on the characteristics of jet ring - spun yarns has been studied. Regular and jet ring-spun yarns of 19.68 tex, 14.76 tex and 11.81 tex have been produced and then tested for hairiness, tensile and evenness properties. Surface features of all these yarns are compared by scanning electron microscopic studies. It is observed that the jet ring-spun yarns display lower hairiness and higher tenacity. The study further suggests that for achieving a reduction in hairiness and good strength with better evenness properties, the use of single brass nozzle will suffice which would lead to considerable reduction in quantity of air used and enable the piecing to be done more easily in ring frame.

Keywords: Air-jet nozzles, Air pressure, Aluminium, Brass, Jet ring - spun yarns, Teflon

IPC Code: Int. Cl8 D02G3/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 53-56

 

 

 

Effect of chitosan treatment on the properties of turmeric dyed cotton yarn

 

T Kavitha, R Padmashwini, A Swarna, V R Giri Dev ,  R Neelakandan & M Senthil Kumar

Received 24 July 2005; revised received and accepted 6 February 2006

Cotton yarn has been coated with different concentrations of chitosan solution and then dyed with turmeric to study their effects on yarn properties. It is observed that the tensile strength, flexural rigidity and shear strength increase with the increase in chitosan concentration. However, the coefficient of friction decreases with the increase in chitosan concentration. Cotton yarn coated with chitosan is found to be darker compared to uncoated yarn while dyeing for the same shade percentage. The dyed yarn coated with chitosan exhibits excellent activity against bacteria, such as E.coli and S.aureus.

Keywords: Chitosan, Colour strength, Cotton, Dyeing, Turmeric ,Yarn properties

IPC Code: Int. Cl.8 A61F5/00; D02G3/00; D06P1/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 57-61

Effect of mass of seed cotton and its lint quality on yarn properties

 

N M Imayathamizhan, K Raghunathan & M R Srikrishnan

Revised received 6 February 2006; accepted 13 April 2006

Reduction in variation of fibre properties within particular fibre groups to get excellent fibre and yarn qualities from the available raw material and categorization of seed cotton prior to ginning with respect to their mass has been explored. For appropriate utilization of raw material to produce yarn of a particular quality, the manually picked seed cottons were grouped with respect to their mass measured with an accuracy of 0.001g. The grouped seed cottons were then ginned on roller gin with four different roller and beater speed combinations and fibres of each group were tested using AFIS and HVI as per the standard procedure. The yarn samples were produced as per the sequence of process used for carded cotton yarn. The separation of the seed cottons with respect to their mass results in the categorization of fibres with respect to their physical properties. The higher mass of seed cotton results in superior fibre properties and vice versa. Similar to fibre properties, a significant enhancement in yarn quality is also observed, particularly in the samples ‘101-150mg’ and ‘151-200mg’ for both 50s and 60s Ne count yarns.

Keywords: Cotton, Ginning, Lint quality, Yarn quality

IPC Code: Int. Cl.8 D02G3/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. e62-71

 

 

Geometrical modelling of plain weft knitted fabrics

Savvas G Vassiliadis, Argyro E Kallivretaki & Christopher G Provatidis

Revised received 20 March 2006; accepted 25 April 2006

The accuracy of the prevailing geometrical models of the plain weft knitted fabrics is estimated and a more precise model for the use in computational modelling produced. The new proposed model is based on the assumptions of the ideal elastic yarn and the elastic energy minimization of the yarns composing the relaxed fabrics. Thus, a repeated calculation process is used for the selection of the loop shape corresponding to the minimum loop length. The accuracy of the models is evaluated using the loop length as criterion. Based on the structural data of an extended set of samples, the loop length for every model is calculated. These values are compared to the respective experimentally measured ones. The accuracy of the new proposed model guarantees the success of the mechanical simulation of the knitted fabrics.

Keywords: 3D geometry, Analytical model, Computer-aided design, Knitted fabric, Loop length, Single jersey fabric

IPC Code: Int. Cl.8 D04B1/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 72-79

 

 

Comfort properties of non-conventional light weight worsted suiting fabrics

 

B K Behera & Rajesh Mishra

Received 22 November 2005; accepted 31 January 2006

Mechanical and thermal comfort aspects of fabrics produced from some non-conventional blends and light weight constructions have been examined. Single yarn woven worsted suiting fabrics show better physical as well as physiological comfort-related properties. Among various natural fibre based worsted suiting fabrics, the linen blend proves to be most suitable with respect to mechanical comfort. Wool and wool:silk blends provide very good transmission properties. Fabrics produced from single worsted yarns are found to be superior to those of the equivalent 2-ply yarns as regards to both mechanical and thermal comforts.

Keywords: Air permeability, Fabric handle, Thermal insulation, Water vapour permeability, Worsted suitings

IPC Code: Int. Cl.8 D03D

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 80-87

 

 

Static and kinetic frictional characteristics of staple fibres and woven fabrics

 

A Das  & S M Ishtiaque

Received 7 February 2006; accepted 21 March 2006

An instrumental has been developed for measuring static and kinetic frictional characteristics of staple fibres and fabrics. The influence of fibre length and fineness on static and kinetic frictional characteristics of polyester and viscose staple fibres has also been studied. A comparative study has been carried out to ascertain the difference in frictional forces measured by an attachment fitted with Instron tensile tester. The developed instrument is also used to study the frictional characteristics of acrylic staple fibres at different levels of finish application. A wide variation in frictional characteristics is observed among different varieties of cotton, even within same variety from different place of origin. It is also observed that warp density and fabric thickness have good correlation with static and kinetic frictional properties of both warp-on-warp and weft-on-weft motions.

Keywords: Cotton, Frictional index, Kinetic friction, Polyester, Staple fibre, Static friction, Viscose, Woven fabric

IPC Code: Int. Cl.8 D03D, G01N33/36

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 88-92

 

 

Antimicrobial activity of cotton fabric treated with Quercus infectoria extract

 

Deepti Gupta  & Ankur Laha

Received 27 January 2006; revised received and accepted 20 March 2006

Cotton fabric has been treated with the tannin-rich extract of Quercus infectoria (QI) plant in combination with alum, copper and ferrous mordants and then tested for antimicrobial activity against Gram- positive and Gram-negative bacteria. QI extract shows good activity at 12% concentration (owf), inhibiting the microbial growth by 45-60%. The microbial growth inhibition increases to 70-90% when alum and copper sulphate are used for mordanting. However, the antimicrobial activity is completely lost when ferrous sulphate is used. The activity of samples treated with QI alone is lost completely after 5 launderings while the mordanted samples retain nearly 100% activity up to 5 launderings, indicating that the mordants help to make the effect durable. The study also shows that the cotton textiles can be successfully treated with QI to produce bioactive textiles from natural ecofriendly materials. QI is a viable alternative to synthetic antimicrobial agents for use in hospital textiles and an effective antiodour agent for use in sports and household textiles.

Keywords: Antimicrobial activity, Bioactive textiles, Cotton, Natural Dyes, Quercus infectoria

IPC Code: Int. Cl.8 A61K9/70, D06M13/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 93-98

 

 

Wetting behaviour of raw and water-repellent cotton fabrics using

wetting kinetic measurements

 

M Mazloompour, N Ansari & N Hemmatinejad

Received 27 September 2005; revised received and accepted 17 March 2006

An electrical resistance technique has been developed to study the rate of horizontal wicking of different liquids into untreated and finish treated cotton fabrics by estimating the critical surface tension of both the fabrics and equivalent capillary spaces of fabric samples from the experimental work based on Washburn derivation. The finishing agents, namely Perlit based on modified fatty acid derivatives and Baygard 430 AFF with a fluorochemical base, have been used. It is observed that the penetration rate and wicking distance of finish treated samples reduce as compared to those of untreated samples. The results confirm different solid-vapor surface tension of the two types of samples due to the changes in surface characteristics of fabrics after finishing treatment. The radii of open channels which act as capillary tubes tend to decrease, leading to blockage of the tube during water-repellent finishing treatments.

Keywords: Capillary wicking, Cotton fabric, Solid surface tension, Water-repellent agent, Wetting

IPC Code: Int. Cl.8 D06B3/00, D06C

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 99-107

 

 

Imparting antimicrobial and fragrance finish on cotton using chitosan with
silicon softener

Anjali Karolia  & Snehal Mendapara

Revised received 2 January 2006; accepted 12 May 2006

Chitosan has been used in combination with citric acid and silicon softener to impart antimicrobial and fragrance finish with two different application techniques. It is observed that the finish provides better functionality to the fabric as it shows good performance and improvement in physical properties. The finish shows good fastness to washing as well as perspiration. The use of carboxylic acid also improves the affinity of chitosan for cellulose.

Keywords: Antimicrobial finish, Chitosan, Fragrance finish, Microencapsulation, Silicon softner

IPC Code: Int.Cl.8 A61K9/70, D06M13/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 105-113

 

 

Synthesis and characterization of aqueous UV-curable binder for ink preparation in ink-jet printing and pigment dyeing of fabrics

M M El-Molla

Revised received 6 February 2006; accepted 27 March 2006

An aqueous UV-curable binder of polyurethane acrylate based on glycerol ethoxylate-co-propoxylate triol has been prepared for ink preparation in ink-jet printing and pigment dyeing of cotton, viscose, wool, polyester and nylon 66 fabrics. Polyurethane acrylate oligomers have been prepared from isophorone diisocyanate, glycerol ethoxylate-co-propoxylate triol and hydroxy ethyl acrylate using dibutyl tin dilaurate as a catalyst. The results show that the binder can be used safely in preparing ink for ink-jet printing and/or for dyeing by padding technique for all types of  fabrics with pigment dyes.

Keywords: Cotton, Ink-jet printing, Nylon 66, Pigment dyeing, Polyester, UV-curable binder, Viscose, Wool

IPC Code: Int. Cl.8  D06P5/30

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 114-118

 

Use of triclosan as antibacterial agent in textiles

Mehmet Orhan, Dilek Kut & Cem Gunesoglu

Received 4 October 2005; revised received and accepted 27 November 2006

The triclosan has been applied on cotton fabrics as an antibacterial agent and its durability to repeated home laundering studied. To evaluate the effects of environmental conditions on activity of triclosan, the samples were exposed to acidic, basic and synthetic urine solutions as simulated wearing conditions. The antibacterial activity of fabrics was evaluated against S. aureus and E. coli. The results show that the raw fabrics have the lowest activity and the bleaching pretreatment causes the increase in antibacterial activity and significant reduction in bacteria growth. However, the fabrics show the best activity after finishing with triclosan, especially against S. aureus. It is also observed that the repeated home laundering, and acidic, basic and urine conditions cause the decrease in the activity.

Keywords: Antibacterial activity, Cotton, Triclosan, Wear conditions

IPC Code: Int. Cl.8 D06B3/00

 

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 119-121

 

 

 

Application of poly (lactic acid) fibres in automotive interior

 

Subhas Ghosh  & Sukanya Krishnan

Received 16 August 2005; revised received and accepted 21 February 2006

The application of poly (lactic acid) [PLA] based fabric for automotive interior application has been studied. It is observed that the PLA fabric meets almost all performance specifications formulated by an original equipment manufacturer, except for flammability and abrasion resistance. The performance of PLA fabric has also been compared with a polyester (PET) automotive fabric and it is found that the PLA fabric often perform equally or better in some properties than PET fabric in all performance parameters, except for abrasion resistance and flammability.

Keywords: Flammability, Flex, Poly (lactic acid), Polyester, Seam

IPC Code: Int.Cl.8 D01B

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 122-125

 

Antimicrobial activity of cotton fabric pretreated by microwave plasma and dyed with onion skin and onion pulp extractions

Chonyu Chen  & Wen-Ya Chang

Received 16 November 2005; revised received and accepted 10 March 2006

Onion has been extracted to obtain colour compound for dyeing cotton fabric and the antimicrobial property of dyed fabric studied. The fabric is first desiccated with ethanol and then pretreated with low-temperature microwave plasma for 4 s with oxygen pressure of 0.2 Torr and power of 800 W. Thereafter, the plasma-treated samples are grafted for 10, 30, 60 min at 70 oC with onion skin and onion pulp extractions. The best inhibition zone of anti Staphylococcus aureus is found to be 1.1-0.8 cm by 10 min grafting time of onion skin extraction and 0.7-0.5 cm by 30 min grafting time of onion pulp extraction. The samples with 10 and 30 min grafting of both onion skin and onion pulp show anti S. aureus ability even after 5 times test washing, but both the samples lost their anti S. aureus property with 60 min grafting. The FTIR-ATR spectrum of dyed cotton fabric shows flavonoids’ functional peak at 1624 cm-1 of onion skin that provides cotton fabric brown colour with wash fastness rating of 4.

Keywords:   Allium cepa, Antimicrobial activity, Cotton fabric,  Microwave plasma, Onion pulp, Staphylococcus
                     aureus

IPC Code: Int. Cl.8 A61K9/70, D06M13/00, D06P3/00

 

Indian Journal of Fibre & Textile Research

Vol. 32, March 2007, pp. 126-134


Parameters involved in assessment of dry state colour of fabrics
from their wet state colour

M Senthilkumar & N Selvakumar

Revised received 19 January 2006; accepted 27 March 2006

One of the parameters that affects the colour appearance of a given material is the moisture content. The wet to dry colour change slows down the process of colour matching because, in present practice, a sample from a dyebath must be dried before it can be assessed. The process would be much more efficient if the colour of the sample when dry could be accurately predicted from the colour of wet sample taken fresh from the dyebath. The dry colour of fabric is affected by parameters such as refractive index of medium and moisture. Studies have been carried out to examine the effect of moisture content on the colour appearance of the dyed textile materials and proposed a geometric model to predict the dry reflectance value from wet materials. The use of refractive index of the embedding medium and the modified Kubelka-Munk equation to predict the dry reflectance value from wet materials have also been studied. In this paper, various parameters that affect the dry colour of fabric, their measurement and various approaches used for the assessment of dry state colour of the fabric from its wet state colour have been reviewed.

Keywords: Kubelka-Munk equation, Reflectance value, Refractive index

IPC Code:  Int. Cl.8 D06P5/00