Reflectory Method for Measuring Tinting Strength of Pigments

概要

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Various coloured pigments were mixed with zinc white and luminous reflection Yc was measured by a recording spectrophotometer. Yc, values were then transformed to Munsell values Vy. The plots of Vy values against the logarithms of weight ratio of the coloured pigment to zinc white gare sigmoidal curves which could be regarded as straight lines within a narrow range and parallel with each other. If it is statistically acceptable that the Vy-log (wt. ratio) plots for the standard and sample pigments are straight and parallel with each other, the logarithm of tinting strength, log (T. S.), can be calculated from log (T.S.) = Vy (A)-Vy (B) /b where Vy (A) and Vy (B) are the Munsell values of the standard and sample pigments, respectively and b the regression coefficient of the standard pigment.<BR>Six kinds of ultramarine were blended in an acrylic resin with zinc white at four levels of weight ratio (four repititions). The luminous reflectances of the 96 films obtained were measured and transformed to Munsell values. The regression equations for the six pigments were calculated by the methods of least squares. The tests of linear regression showed that three of the six regressions fitted to linear equation. The tests of significance of difference in the regression coefficient of the standard pigment with those of the sample pigments showed that they could be regarded as parallel with one another.
Japan Society of Colour Materialの論文