A review of lcam datasets and sève whiteness proposal

Abstract

In our recent work, we investigated the validity of the newly proposed whiteness formula by Robert Sève [1] for our LCAM whiteness datasets under a LED light source of correlated color temperature (CCT) 5000K combined with Wood's UV-A lamp.We compared the CIE whiteness formula, the Ganz whiteness formula, and the Séve proposal to the results of visual assessment of forty white samples assessed by ten observers with normal color vision under experimental light source. Because the Sève proposal was derived from the CIE formula for whiteness considering whitespace, we were interested to see its impact on our datasets under test lighting different from D65.We have found that the Sève whiteness formula can predict maximum whiteness as a function of saturation for light conditions other than CIE D65, but visual observations of whiteness lead to an assessment of a significant drop in whiteness for materials with saturation between - 40 and -70 and luminance factor between 70 and 90. As expected, both the CIE whiteness formula and the Ganz formula correlated strongly with visual observations. In the case of the CIE equation, a high correlation coefficient of 0.84 was measured compared to the newly proposed W2,n equation where a value of 0.71 was found. In other words, with a very intense UV source, the intensity of which is above the UV fraction of the corresponding CIE illuminations D, the colouration of the samples containing FWA is highly saturated. This fact is not taken into account in the case of the CIE equation. Dr. Sève's new proposal addresses this problem, but sufficient new visual experiments need to be set up so that the parameters of this equation can be optimised.