AATCC EP4-2006

1. Scope

1.1 This evaluation procedure describes the use of the standard depth scales for the determination of the dye concentration required to produce dyeings of visually equal depth for the purpose of colorfastness evaluations. Colorants may have different tinctorial strengths whereby equal concentration dyeings of them may differ markedly in the resulting color depth and colorfastness properties. Using concentrations of colorants which will give visually equal depths will provide a more comparable evaluation.

2. Principle

2.1 Dyeings at a given concentration of dye are compared visually to the standard depth scales following the guidelines in AATCC Evaluation Procedure 9, Visual Assessment of Color Difference of Textiles. If the perceived depths are not equal, the dye concentration of the test specimen is adjusted until it is judged to be visually equal in depth to a specimen on the standard depth scales.

2.2 The standard depth scales consist of six sets of 12-18 fabric dyeings of different hue and chroma and one set specifically for navy and black shades. All of the dyeings in any set are considered to be of visually equal depth.