1. Grey Scale for Assessing Change in Colour EN ISO 105-A02
This Grey Scale is for assessing changes in colour of leather in colour fastness tests, for example, wash fastness, perspiration fastness, etc.
The scale consists of nine pairs of grey colour chips each representing a visual difference and contrast. The fastness rating goes step-wise from:
Note 5 = no visual change (best rating)
to Note 1 = a large visual change (worst rating).
The grey scale has the 9 possible values: 5, 4-5, 4, 3-4, 3, 2-3, 2, 1-2, 1.
It is now quite common to measure the Grey Scale change in colour instrumentially. This is made using a suitable reflectance spectrophotometer according to the test method procedure, EN ISO 105-A05.
2. Grey Scale for Assessing Staining EN ISO 105-A03
This Grey Scale is for assessing the degree of staining caused by a dyed leather in colour fastness tests. For example, the staining of wool and cotton fabrics in the wash fastness, perspiration fastness, etc.
The scale consists of nine pairs of grey colour chips each representing a visual difference and contrast.
The fastness rating goes step-wise from:
Note 5 = no visual change (best rating)
to Note 1 = a large visual change (worst rating).
The grey scale has the 9 possible values: 5, 4-5, 4, 3-4, 3, 2-3, 2, 1-2, 1.
It is now quite common to measure the Grey Scale for assessing staining instrumentially. This is made using a suitable reflectance spectrophotometer according to the test method procedure, EN ISO 105-A04.
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