Many products - such as textiles, inks/paints/coatings, plastics, paper, - are coloured with dyes and pigments. These colours can fade or change when the products are exposed to water, light, rubbing, washing, perspiration etc.
Colour fastness is the resistance of a material to change in any of its colour characteristics, including the transfer of its colourants to adjacent materials;
Fading means the colour changes and lightens;
Bleeding is the transfer of one colour to another material. This is often expressed as soiling or staining.
Fastness properties respectively qualities are expressed in ratings. These fastness ratings are evaluated by grey scales for bleeding and fading. They consist of five different grey colour graduations and are compared with tested textile and its prescribed adjacent material. The ratings are:
Only light fastness ratings are evaluated with blue scales from 1 )very poor) to 8 for the best colour fastness.
Various textile chemicals depending on fibre composition of the fabrics can be used. Generally dyed fabrics are undergoing a treatment after the washing process with chemicals for better fibre colour fixation.
During textile dying and after-treatment washing restricted or banned chemicals can remain in the fabrics. This can be prevented by good manufacturing processes.
For the chemical risk assessment of materials this is essential information from your supply chain.