A new method for determining relative colour strength of dye based on new colour depth formulas. Part I: For different dyes with approximate hue

Abstract

Relative colour strength (RCS) of dye plays an important role in the production, the evaluation and the application of dyes. There are different standards on the determination of it, their principles are all related to colour depth. However, the standard methods have some limitations. For this purpose, this study proposed a new method for the RCS based on the new colour depth formula Yangn, which included three methods named colour strength value (CSV1, CSV2 and CSV3). Part I in this study was to investigate the application effect of Yangn on the RCS of different disperse dyes with approximate hues. According to the experimental results of E-type and SE-type disperse dyes, the new method showed its advantages. Firstly, compared with AATCC EP-6, the results of the new method were more consistent. Secondly, under different dyeing concentrations, the RCS values of the new method were relatively consistent, with average coefficient values (CVs) being less than 5%, especially for CSV3 with only 3.59%; while all the average CVs of AATCC EP-6 were greater than 6%. For the calculation of RCS of different types of dyes with approximate hue, the new method presented more accurate results.

A new method for determination of the relative colour strength of dye based on new colour depth formula. Part II: application to different batches of colourant

“…Part I tested the calculation effect of Yangn on different types of dyes that had approximate hue. 20 The work outlined in Part II of our study (this article) focused on relative colour strength of different production batches of the same dyes.…”

“…In this study, the new methods Yang n (CSV1, CSV2, and CSV3) for the determination of RCS were proposed with the help of the colour depth formula Yang n . Part I tested the calculation effect of Yang n on different types of dyes that had approximate hue 20 . The work outlined in Part II of our study (this article) focused on relative colour strength of different production batches of the same dyes.…”

“…19 Part I of this study has detailed information on these formulas. 20 In the actual operation, for the GB/T 6688, it is necessary to dye multiple times to obtain the qualified samples. As the common methods for calculating the RCS, 10,21 the US standard of AATCC EP-6 does not require the dyeing depth, it uses the ratio of the colour strength value per unit concentration from the sample dye and the standard dye, 22 it contains three methods for calculating the colour strength value: SWL (equate to K/S), SUM and WSUM, see Part I of this study for these formulas.…”

“…Chinese standard of GB/T 6688 requires the test samples and standard samples to be dyed to the one‐third standard depth, 18 and then the ratios of the concentrations of test dyes and standard dyes are used to calculate the RCS, it includes two methods to calculate colour depth (colour strength value): K/S and I value 19 . Part I of this study has detailed information on these formulas 20 …”