Colors that are lighter than the surrounding unaffected areas are the result of color loss. Colors that are darker than the surrounding unaffected areas are the result of something added. Shades that end-up changing in different light and diminish or disappear in direct intense light are the result of texture variations, usually from over aggressive mechanical action.
An inspection report involving a color loss from defective dye due to forces of nature requires a laboratory test for either light, o-zone, or gas fading. Of these, only light fading has recognition from UM 44. My own professional opinion is that anything below a '4' after two cycles of testing constitutes a defect in manufacturing. Four or over indicates a problem of too much light, ozone, or gas, etc. The test for each of these is as follows:
Use the company below for your testing.
An inspection report involving a color loss from defective dye from bleeding or crocking can occur on multicolored nylons where cross dyeing has been used. In this system, one dye bathe dyes the carpet two different colors. One of the dyes will be an acid dye and the other will likely be cationic. The cationic dye will attach to a modified nylon, but sometimes will not remain color fast when cleaned with anionic detergents, like CHEMSPEC ONE CLEAN, FORMULA 77, or PROCHEM DRY SLURRY, or STEAM GENIE FABRIC RINSE. Thus this problem shows up as a result of cleaning. The test using the Gray Scale Card is rated between '1' and '5'. From a professional opinion, anything below a 'four' is a defect.
Examples of color loss problems are:
American Association of Textile Chemists and Colorists