| 摘要 |
1,213,479. Exposure regulation in a colour printing process. AGFA - GEVAERT A. G. Dec.8, 1967 [Dec.10, 1966], No.55891/67. Heading G2A. In printing from colour transparencies, light in each of the three primary colours from a multicoloured original is transmitted separately to a light receiver of a photo-electric exposure regulating device, and under-correction is obtained by arranging that at least one of the light receivers receives an amount of light of the other two colours, varying with the required degree of under-correction. As shown in Fig. 1, white light from a source 1 passes through an original 3 and is focused by an objective 4 on copy material 5, sensitive to the three primary colours. A mirror 7 partially reflects light through a set 8 of composite filters to secondary electron multipliers 9,10,11, which through a regulating device 12 energize electromagnets 16,17,18 to move subtractive colour filters 13,14,15 into the copying light path to terminate the exposure. Each composite filter (22, 23, 24) Fig. 2 (not shown) comprises a primary colour filter and an equal density grey filter, and the filters are moved by connected holders (25, 28) to vary the proportions of primary colours incident on the electron multipliers. The single light source may be replaced by three primary colour light sources. |
