The COLOR OF WINE: A HISTORICAL PERSPECTIVE. I. SPECTRAL EVALUATIONS.

In the 1930s trade transactions required that the color of wine be more rigidly specified. The wine-colorimeter was useful with this purpose. Intensity of color was the first property to be considered. From the beginning of this century visual comparisons of wines with standard mixtures of dyes or colored substances (potassium permanganate and dichromate) were made. Later photometric studies (absorption curves) were developed. Maxima and minima in the absorption curve were defined, as well as their relationships. Recently, it has been shown that absorbance values at given wavelengths and luminosity are well correlated.