| 摘要 |
1275069 Photographic silver halide materials with wide exposure latitude EASTMAN KODAK CO 16 May 1969 [20 May 1968] 25122/69 Heading G2C A photographic material comprises a support carrying two light-sensitive silver halide emulsion layers having different photographic speeds but sensitive to the same region of the spectrum, the slower layer containing a non-diffusible photographic image-forming coupler and a non- diffusible development-inhibitor-releasing (DIR) coupler, the faster layer containing a non- diffusible photographic image-forming coupler and having a higher effective photographic speed than said slower layer. The faster layer preferably has an effective photographic speed at least 0À6 log exposure units higher than the slower layer. Many examples are listed of couplers. The DIR coupler preferably carries a heterocyclic monothir radical in its coupling position. Other DIR couplers include α-{3-[α-(2,4-di-tertamylphenoxy) butyramido]benzoyl}-α-(2- aminophenylazoxy)-2-methoxyacetanilide and α-{3-[γ-(2,4-di-tert-amylphenoxy)butyramido]- benzoyl-α-(2-amino-4-methylphenylazoxy)-2- methoxy-acetanilide. The light-sensitive silver halide emulsion layers may be separated from the support by a non-image recording silver halide emulsion layer in which the silver halide grains have an average diameter of less than 1 micron. The non-image recording layer may have a thickness of 10-40 microns, and reduces image spread. Both the slower and faster layers may contain cyan-forming couplers and the DIR coupler may form a cyan dye (see Example). The light-sensitive silver halide emulsion layers may be separated from the support by an antihalation layer. The DIR coupler in the slower layer extends exposure latitude and reduces contrast. These materials can record images of vastly different intensity in close geometrical proximity with minimal image spread, and exhibit excellent sharpness. They produce high contrast records of faint images and low contrast records of bright images. Reference has been directed by the Comptroller to Specification 953454. |
