| 摘要 |
509,308. Photographic processes. KODAK, Ltd., SELWYN, E. W. H., and BOWYER, C. H. Jan. 11, 1938, No. 938. [Classes 97 (i) and 98 (ii)] A reversed monochromatic light-image of an object or transparency, i.e., an image in which the bright parts of the object appear dark and vice versa, is produced by projecting an image in substantially infra red light on a luminescent screen maintained in a luminescent state by radiation consisting substantially of wavelengths shorter than the visible, the luminiscence being reduced by the infra-red light. As shown an image of a transparency 1 is projected on to a fluorescent screen 8 by a source 2 of infra-red light, condensers 3, 4, a filter 6 and projection lens 5 and mirror 7, the screen being simultaneously irradiated by ultra violet light from a source 9, the intensity of which is controlled by a variable light-wedge 10 or by a diaphragm. The infra red beam may be similarly controlled. The screen 8 may be carried on a transparent or opaque support, and the former case a filter dyestuff is provided to absorb the ultra-violet light passing through. The transparency 6, which may be a negative, may be placed in contact with the screen to produce a positive image. |
