Interaction Between Saturation and Lightness of Pigmented Samples

It is known that saturation and lightness are interdependent dimensions of colored surfaces. In the present study we are attempting to describe the interaction between those two variables in quantitative terms. We have noticed before (1,2) that when comparing samples of the same hue and colorimetric purity (Pc) but different reflectance (R), the observers (Os) assigned different values of saturation whether the hue were mixed with white or black. Also the discrimination of chromatic lightness varied in a different manner for high levels of reflectance as compared with lower levels. Our main concern in this work is to examine more closely these effects by dividing each chromatic continuum in two ranges of reflectance: one where samples move from pigment to white (P+W) and the other, ranging from pigment to black (P+B).