The samples were assessed against the standard gray scale for colour change (ISO 105 A02) and staining of adjacent mul-tifiber (ISO 105 A03). A rating scale consists of pairs of stan-dard gray chips, the pairs representing progressive differences in colour or contrast corresponding to numerical colourfast-ness grades, the numerical value that is assigned to the change in colour of a test specimen as compared to an original speci-men. The rating scale was 1 (poor) to 5 (excellent).