NOTE: This definition was changed in RP-16-17 Addendum 4. Deletions have a strike-through. New text is bold.
A quantity (pc) defined by pc = L1/(L1 + L2), where L1 is the luminance of a single-wavelength (monochromatic) light source, and L2 is the luminance of the reference standard light source. These values are obtained by adjusting the reference standard light source until the additive mixture of the two match the color of the considered light source.« Back to Definitions Index