A Color Notation

"[...] INTRODUCTION. The lack of definiteness which is at present so general in color nomenclature, is due in large measure to the failure to appreciate the fundamental characteristics on which color differences depend. For the physicist, the expression of the wave length of any particular light is in most cases sufficient, but in the great majority of instances where colors are referred to, something more than this and something easier of realization is essential. The attempt to express color relations by using merely two [...]".