Q4: Test for colour fastness Flashcards
Colourfastness
Colourfastness is the property of a dye or print to retain its colour and shade during the lifetime of its intended use.
Various tests are available to simulate the environmental con- ditions that may cause colour changes and fading. In some of the tests, the transfer of colour is as important as the change in the original colour.
The amount of colour change is usually evaluated by comparing samples with standards (eg grey scales) and with the original fabric.
Colourfastness tests include the following :
Colourfastness to washing
Colourfastness to dry-cleaning
Colourfastness to light
Other tests assess the colourfastness of textiles
to ironing, hot pressing, water, chlorine bleach, chlorinated water and seawater.
Colourfastness to washing
Colourfastness to washing relates to laundering under appropriate conditions of temperature, bleaching and abrasive reaction. The test may be done using laboratory test equipment or full-size washing machines.
Colourfastness to dry-cleaning
Colourfastness to dry-cleaning entails determining the resistance of the colour of textiles to all types of dry-cleaning.
Colourfastness to light
Colourfastness to light involves determining the resistance to degradation of dyes and prints to light. Exposure may be to actual sunlight or artificial light sources. Artificial light sources allow for accelerated testing. In all cases, reference standards are used to determine exposure.
tests
Various tests are available to simulate the environmental con- ditions that may cause colour changes and fading.
In some of the tests, the transfer of colour is as important as the change in the original colour.
The amount of colour change is usually evaluated by comparing samples with standards (eg grey scales) and with the original fabric.
Colourimetric measurements may also be done, using a spectrophotometer.
