Computer colour matching with fluorescent dyes : The influence of fluorescence on reflectance - concentration relationships for fluorescent dyes, singly and in mixtures, and the effects on the prediction of recipes for use in colour matching.

Abstract

A simple and feasible method of computer colour matching involving fluorescent dyes was developed. An ordinary abridged-spectroreflectometer with polychomatic illumination and a simulated D65 xenon light source was employed for all measurements. In addition to the normal K/S constants for non-fluorescent dyes and the non-fluorescent portion of the fluorescent dye'.. constants responsible for the fluorescent portion were necessary. Two sets of equations to relate the total radiance factors of dyeings with a fluorescent dye and its concentration were developed respectively for self and compound shades where a non-fluorescent dye is admixed. Finding constants responsible for the compound shades required a number of calibration mixture dyeings. Negative K/S constants were found useful when the total radiance factor was above that for the substrate but below one hundred. Three computer programs? s were developed to deal with calibration constants for self and compound shade and also for match prediction. Optimization was used in all cases to minimize errors in total radiance factors or colour differences. Half of the actual dyeingq formulations from the predicted were visually passed by a panel of five dyers. In this study, disperse dyes on polyester were used. Moreover, a commercial matching package was studied using non-fluorescent dyes. The dyeing system affected its accuracy. The polyester/disperse dye system was better than the cotton/reactive dye system. The sample size and luminancefactor of target colours; were also studied. The accuracy was affected slightly by the latter but not the former.