There are two kinds of representation methods ness as the test light. The quantity L* is the metric of the Helmholtz-Kohlrausch effect; one is the Variablelightness of test chromatic object color, and L* N is its Achromatic-Color method, and the other the Variableequivalent lightness or the metric lightness of reference Chromatic-Color method. The following three items are achromatic object color with the same perceived lightness described in detail. ( ) How to use and adapt the predicas the test color. β For the reference white light and the tion equations of the two methods to their practical appliillumination for object colors, illuminant C was used in cations. ( ) Theoretical derivations of the prediction the previous study, 10 and is also used in the present article.
equations in both methods, and clarification of the simple
As already described in the previous article, 10 the four relation existing between the numerical coefficients used kinds of prediction equations reported have extensive apin the prediction equations on the two methods. (3) Logiplications in the H-K effect.
cal consistency between the long series of studies on the
The present author, however, has received the follow-H-K effect by the author and his colleagues. α§ 1998 John ing three questions from some of the experts in this field: