ELECTRONIC SPECTROSCOPY AND TRICHROMATICITY COLORIMETRY OF SOME INORGANIC PIGMENTS AND THEIR MIXTURES

Electronic spectroscopy and trichromaticity colorimetry were applied t o study chrome yellow and iron blue mixtures. The colour of these pigm ent mixtures was determined on the basis of reflectance spectra and de scribed in the CIE, CIELAB, CIELUV colour spaces. It was found that va rious ratios of the components change the intensify of the reflectance spectra, whereas the band positions exhibit only small deviations fro m those of the pure components. The changes in the pigment concentrati ons give rise to a nonlinear variation of chromaticity coordinates. In the samples of mixtures containing an identical quantity of iron blue , the same colour differences were observed. Our experimental data sug gest that this method can be applied to improve the analysis of the co lorant compounds.