MATERIELS PHOTOGRAPHIQUES, PROCEDES DE FORMATION D'IMAGES EN COULEURS ET APPAREIL D'EXPOSITION

A radiation-sensitive element for half tone color proofing adapted to be exposed by scanning with four independently modulated sources of radiation emitting at different wavelengths within the range 550 to 900 nm, the element comprising a substrate bearing at least four separate imaging media coated thereon, said imaging media including: (1) an imaging medium capable of forming a yellow image upon imagewise exposure and processing, (2) an imaging medium capable of forming a magenta image upon imagewise exposure and processing, (3) an imaging medium capable of forming a cyan image upon imagewise exposure and processing, and (4) an imaging medium capable of forming a black or a balancing black image upon imagewise exposure and processing, each imaging medium having a maximum spectral sensitivity at a wavelength different from that of the maximum sensitivity of the other imaging media such that after exposure and processing super-imposed yellow, magenta, cyan and black or balancing black images are formed, each image being attributable to the imagewise exposure of the respective source. Three layer elements of forming yellow, magenta and cyan images may be used for preparing half-tone full color images. Exposure apparatus comprising at least three independently modulated sources, preferably semi conductor sources emitting in the region of 550 to 900 nm may be used for imaging.