1.1 This standaid prescribes methods for assessing the re sistance of colour on dyed textiles, both natural and man-made, in whatever form they may be, i.e., loose fibre, yarn or manufac tured fabric, dyed or printed with any dyes and in any shade, to the action of soap solution as used in washing.
1.2 In view of the diversity of requirements in fastness to washing, four tests of increasing severity are prescribed. The practical significance of these tests is as follows:—
(a) Test No. 1: Corresponds to a single mild soap washing.
(b) Test No. 2: is a test of medium severity corresponding in this results to the cumulative effect of five successive mild soap washings.
(c) Test No. 3: Corresponds to a single severe soap washing.
(d) Test No. 4: Corresponds in its results to the cumulative effect of five successive severe soap washings.