AATCC 182:2000 pdf download.Relative Color Strength of Dyes in Solution
5.1 This method is not applicable to all dyestuffs; e.g., pigments, due to solubil- ity and/or other limitations. Dyes that are commonly measured include acid, basic, direct and disperse. Many reactive dyes are not easily measured using this proce- dure.
5.2 Basic requirements for this method are that the dye solutions do not scatter light and do obey the Lambert-Beer or Beer-Bouguer Laws as well as having identical or similar absorption curves of the samples and the reference dyes in the visible region of the spectrum (see 13.9).
5.3 Identical or similar absorption curves are usually obtained if the tests are carried out for the purpose of dye produc- tion control of batches/deliveries of the same dye. This method is not applicable for the evaluation of dyes with distinctly different hues or strengths or chemical compositions.
5.4 The method may be useful in the prediction of relative dye strength in process applications; e.g., dyeing. It is generally accepted that some reasonable correlation can be obtained between ap- plication and solution measurements. Ex- ceptions occur where there is a signifi- cant difference in the relative amount of colored but non-exhausting or non-fixing impurities between the specimen under test and the reference dye; e.g., reactive dyes. Exceptions may also occur for some reactive dyes which exhibit shade differences between their hydrolyzed and unreacted forms (see additional caution for reactive dyes in 8.3.3).
5.5 As the relative color strength is de- termined by a comparison with a refer- ence dye, the reference dye is assumed to remain constant. It is essential, therefore, to ensure careful storage and control of the reference dye. Many dyes are hygro- scopic and sensitive to oxidation. Protect the reference dye from exposure to light in firmly sealed containers that are imper- vious to moisture.AATCC 182 pdf download.