| 摘要 |
845,217. Photographic silver halide materials. AGFA A. G. June 20, 1957 [June 26, 1956], No. 19467/57. Drawings to Specification. Class 98(2) Material for production of records with tone valve correction comprises a support having an inner layer of gamma valve of 0À5 to 0À9, and an outer layer thereover of gamma valve at least 1¢ times that of the inner layer and a speed of 1/20 to 1/80 of such inner layer. The two layers may be sensitive to the same or different regions of the spectrum, with both panchromatic they may be used for production of colour separation records of improved highlight reproduction, the image in the outer layer constituting a mask and such can be reduced if desired with Farmer's reducer without the lower image suffering. In a single example the emulsion disclosed in BIOS-Bericht 1355 page 35 green sensitised with 3, 31, 9-triethyl-5, 51-diphenyl oxacarbocyanine iodide is cast on an acetyl cellulose support and the emulsion of the Fiat Final Report 360, page 24 is cast thereover, and this material is exposed as in a process camera to a black and white original and treated in a specified developer to produce images of gamma valves 2À8 and 0À9 respectively, if exposure is made to a negative original tone valve correction in the shadows is achieved. |
