The Translation of Colours into Black-and-White Photographs

Usual chromatic sensitization of black-and-white films attempts to translate a completely natural subject, rich in tone values and colours. into a monochrome representation. To remind an observer of the subject is only possible when taking both into account. A theoretical spectral sensitivity like that of the eye, neither at normal nor at increased contrast, is satisfactory in spite of the apparent obviousness of its choice, because the exact rendering of relative luminosities must be disturbed if objects of different hue, but of equal visual luminosity, are to be distinguished. The usual chromatic sensitivity of block-and-white films is sotisfactary; it might be improved further by slightly reducing the sensitivity to blue light, and increasing that to green light.