Well, not sure how this works, but apparently Perwoll - a detergent brand which up to my knowledge is new to the market - promises to "clean and renew colors with every wash". Interesting, with other brands issuing forumlas for black fabrics (especially for women's black abayas implicitly) - Perwoll seems to target all colors apparently. Interestingly, Perwoll is a brand owned by Henkel - yes, the same Henkel that also owns Persil. So perhaps Perwoll is a fighter brand launched to take market share from competitors, or perhaps it is the answer to other competitor companies who have specialized formulas to clean colored fabrics.