black, key

black, key (In French noir) process printing ink whose addition compensates for the spectral inadequacies of the chromatic colors CMY. Significance in achromatic and chromatic composition: – “maximum black”: highest tone value that black can achieve in the image shadows (usually 95% in offset printing, seldom more); – “starting point”: the tone value above which black replaces the chromatic colors; – “short black”: supplements/replaces the chromatic colors in the dark tones only; – “long black”: supplements/replaces the chromatic colors right as far as the highlights; – “black length”: describes the black structure along the gray axis or L* axis (CIELAB); – “black width”: specifies how far away from the gray or L* axis black supplements/replaces the chromatic colors; the greater the black width, the more black intervenes in the structure of higher chromaticness C* (CIELAB).