What is the Colourfastness Rating all about with Fabrics?
The Colourfastness rating when applied to Drapery or Upholstery fabric provides in indication of how well the fabric will resist fading from various agencies such as UV light, rubbing and washing.
Fading might be a change in hue, depth or brightness or any combination of these.
Fabrics are tested through rubbing, exposure to light and to washing or a combination of all three tests.
The colour fastness to light uses 8 blue scales which slowly graduate from light to dark and the results are graded from 1-8. 1 is a pretty poor result, whereas 7 would be considered an excellent result.
Generally a rating of 5 or greater is a great rating for drapery fabrics which are likely to be exposed to direct sunlight for prolonged periods. With upholstery, on the other hand, a 4 would be a pretty decent rating as your upholstery furniture is less likely to suffer from as much prolonged direct sunlight as drapery fabric.
The fabric may also be given a wash/dry clean test. With wash/dry clean tests the fabrics are giving a rating on the grey scale. With testing colour fastness to washing/dry cleaning a rating of 5 indicates 'no dye loss' as a result of testing. Once again the scale for washing/dry cleaning is logarithmic. .. so a 5 is double a 4.