Method for determining colorimetric value

Abstract

The colorimetric value at a specified temperature is determined by measuring the colorimetric value of a colored material sample at an arbitrary temperature using a color meter such as a spectrophotometer, colorimeter, or densitometer, and by correcting the measured colorimetric value on the basis of the change in colorimetric value with temperature, which change in colorimetric value is computed from the difference in colorimetric values observed for a single colored material sample at a minimum of two different temperatures. When a spectrophotometer is applied, the spectral reflectance or the spectral transmittance of the colored material sample is measured. On the other hand, spectral reflectance or spectral transmittance is measured in advance for a dye or pigment at a minimum of two different temperatures. The difference (.DELTA.K) of absorption coefficient (K), the difference (.DELTA.S) in the scattering coefficient (S), and the difference (.DELTA.D) in absorbance (D) at each wavelength are computed from the preliminarily observed spectral reflectance or spectral transmittance. The spectral transmittance or spectral reflectance observed at an arbitrary temperature is corrected to define the colorimetric value at a specified temperature using the obtained values of K, S, and D.