Colour fastness:Colour fastness is a term that describes the propensity of an article to change or lose colour when treated in a certain way.The quality of a dyed material possessing resistance against washing, bright light exposition, gas or by rubbing.When exposed to light, gas, water, use, the dyed material does not lose the color.The property of dye that enables it to retain its original colour in its original depth and tone throughout the wear life of the product to which it has been applied

Standard organization

AATCC ASTM BSI BIS ISO

Factor Washing Rubbing Daylight Artificial light Perspiration Dry cleaning Heat setting Sublimation

Assessment of colour fastnessChange in colour ( of the test- specimen)Staining( of adjacent fabric)

Grey ScalesBefore talking about any textile test or test method, it is very necessary to have the knowledge about Gray scales.Two types of gray scales are used below are the types and usage of them:

Grey Scale for Assessing Change in Shade Assessing the degree of change in shade caused to a dyed Textile fabric / yarn in color fastness tests The scale consists of nine pairs of gray color chips each representing a visual difference and contrast The fastness rating goes step-wise from: Note 5 = no visual change (best rating) Note 1 = a large visual change (worst rating). The gray scale has the 9 possible values: 5, 4-5, 4, 3-4, 3, 2-3, 2, 1-2, 1.

GREY SCALE FOR ASSESSING STAINING

This Grey Scale is for assessing the degree of staining caused by a dyed Textile / yarn in color fastness tests. The scale consists of nine pairs of gray color chips each representing a visual difference and contrast

The fastness rating goes step-wise from:Note 5 = no visual change (best rating) to Note 1 = a large visual change (worst rating). The grey scale has the 9 possible values: 5, 4-5, 4, 3-4, 3, 2-3, 2, 1-2, 1.

Principle A specimen of the textile in contact with one or two specified adjacent fabrics is mechanically agitated under specified conditions of time and temperature in a soap solution, then rinsed and dried. The change in colour of the specimen and the staining of the adjacent fabric (s) are assessed with the grey scales

If first piece is Cotton WoolSilkLinen Viscose Acetate PolyamidePolyesterAcrylic Second piece to beWoolCotton CottonCottonWoolViscosewool or viscosewool or cottonwool or cotton

Colour fastness to rubbing, Crockmeter (textiles), dry and wet Colour fastness to perspiration Colour fastness to chlorinated water Colour fastness to sea water Colour fastness to laundry Colour fastness to xenon light, dry sample

Colorfastness to Crocking or Rubbing Purpose and ScopeThis test method is used to determine the amount of color transferred from the surface of colored textile materials to other surfaces by rubbing. It is applicable to textiles made from all fibers in the form of yarn or fabric, whether dyed, printed or otherwise colored and especially to prints where the singling out of areas smaller than possible to test with the standard AATCC Crockmeter (AATCC Method 8) Crock master (Crockmeter) is used to determine colour fastness to wet and dry rubbing. Crock master is suitable for colour fastness testing for all types of textiles, including carpets and floor coverings.

PrincipleA test specimen held at the base of the Rotary Vertical Crockmeter is rubbed with standard test squares under controlled conditions Color transferred to the test squares is assessed by a comparison with the Gray Scale for Staining or AATCC Chromatic Transference ScaleTerminologyCrocking, a transfer of colorant from the surface of a colored yarn or fabric to another surface or to an adjacent area of the same fabric principally by rubbing.

Apparatus and MaterialsRotary Vertical Crockmeter Crockmeter Cloth. standard 51 51 mm (2 2 in.) test squares AATCC Chromatic Transference Scale Gray Scale for StainingWhite AATCC Blotting PaperTest Specimens. Materials of nearly any construction presenting a surface area of approximately 25 mm (1 in.) square or more can be tested

ProcedureDry Crocking Test.Place a test square on the end of the vertical rod and fasten it with spring clip.Hold the test specimen on the machine base at the point the vertical rod contacts the base. Place the weight supplied with the Crockmeter on the vertical shaft to give the rubbing finger a downward force of 11.1N 10% (40 oz 10%).With the left hand, hold the test specimen in position on the base. Turn the crank 20 turns with the right hand. This produces about 40 reciprocal turns of the vertical shaft.

Colour fastness to washingTo determine the effect of washing only on the colour fastness of the textileScope:It prescribes a method for determination of colour fastness of textile material like fibre, yarn and fabric to the action of soap solution at 40CPrinciple The fabrics mechanically agitated in soap solution , rinsed and driedThe change in colour and staining are assessed with the std. grey scaleFabric preparation Size is 10 x 4 cm Three size composite specimen

500 ml container, speed 40+2 rev/minsThermostat is used for to control the tempFabric sample size is 10 4 cmMLR 1:50TIME 30 mins

Colorfastness to Heat: Hot PressingThis test method is intended for determining the resistance of the color of textiles of all kinds and in all forms to color change, and color transfer when subjected to ironing or pressing of hot cylinderTests are given for hot pressing when the fabric is dry, damp and wet. The textile end use usually determines which tests should be made.The iron should be capable of giving a pressure of 0.43lb/sq inch and temp of:cotton and linen 190-210 Cwool, silk, and viscose140-160 CCellulose acetate, polyamide115-120CPolyester180-190CThe cloth is pressed for 15sec with a hot iron in three conditions.

PrincipleDry Pressing - Dry specimen placed on dry cotton clothDamp Pressing - Dry specimen placed on dry cotton cloth , another wet squeezed cloth placed on dry specimen Wet Pressing - wet squeezed specimen placed on wet squeezed cotton cloth Hot Pressing, a process for smoothing and possibly shaping textile products by applying mechanical pressure with heat, either dry or in the presence of moisture.