What is the Colourfastness Rating all about with Fabrics?

Updated 3 months ago by Nancy Vamvakas

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.

Light 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.

The important thing to note is that the 1-8 scale is logarithmic, meaning it will take blue scale 5 twice as long to fade to blue scale 4. .. In other words there is a huge difference between a 4 and a 5 (effectively twice the degree of fading).

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.

Wash Tests:

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.

With wash/dry cleaning tests the fabrics are conducted at various temperatures depending on the care instructions recommended by the textile manufacturer. It is therefore important that you understand that your colourfastness rating might mean very little if you ignore the manufacturers care label when washing/dry cleaning your fabric.

What are colourfastness ratings all about on fabrics


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