GB947162A - Improvements in or relating to reproduction of dyeings - Google Patents

Abstract

The colour of a dyeing of an original dye mixture on a carrier is reproduced by separately applying a number of primary colour dyes in a plurality of dyebath concentrations to a plurality of samples of the same dye carrier to be dyed, determining from these dyed samples their spectral reflectance curves, determining the spectral reflectance curve of the original dye mixture, selecting from the spectral reflectance curve of each particular primary colour dye the particular wavelength at which the ratio of the reflectance of that particular primary colour dye to the reflectance of the other primary colour dyes is a minimum, tracing graphically for each of those selected wavelengths the reflectance values of all the primary colour dyes as a function of the dyebath concentration, determining from these graphs the dyebath concentrations of the individual dye components of the dye mixture required to reproduce the colour of the original dye mixture at the reflectance values of the original dye mixture corresponding to the said particular wavelengths, mixing the dye components in a dyebath at the determined dyebath concentrations and dyeing the carrier from this dyebath. The reflectance curve of the reproduced dyeing is determined and compared with the reflectance curve of the original dye mixture and the dyebath concentrations of the dye components are then corrected according to the differences in the reflectance values at the wavelengths at which they were determined.