Cotton cellulose was dyed "in situ" with a polymeric dye generated by oxidative coupling of colourless 2,5-diaminobenzenesulfonic acid and 1-hydroxyphenol (catechol) with laccase. Up to 70% dye fixation was obtained increasing the concentration of catechol less soluble upon oxidation from 1 to 10 mmol, while 1 mmol of diamine was used. Dye fixation was not achieved using equal molar concentrations of the reagents.

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Values obtained by using five colour difference formulae in a set of 106 pairs of textile samples are compared with visual assessments. These included not only total colour difference, but also their psychophysical components (lightness, chroma and hue differences). Visual data used for the comparisons are the average from more than eight observers' assessments, carried out under standardised conditions by means of the grey scale method. Linear regression calculations show that the new CIEDE2000 formula gives similar results to the CMC(2:1) formula, with the differences between correlation coefficients not being statistically significant. The application of performance factors helps to ascertain the superiority of these two formulae over the other three tested. This is valid not only for total colour difference, but also for its individual components.