Title: Direct-positive photographic emulsion containing, unfogged, monodispersed silver halide grains having a layered grain structure of specific silver chloride content

Abstract: A direct-positive photographic material for producing images by fogging development wherein the photographic material contains an unfogged silver halide emulsion layer. The silver halide grains in the unfogged emulsion have a layered grain structure wherein there is a first phase in which is localized a relatively high silver chloride content of at least 20 mol percent based on the total silver halide content of the grain. A second phase contains from less silver chloride than the first phase down to no silver chloride and the total silver chloride in the grain does not exceed 30 mol percent. The physical position of the first phase in the grain is not critical. The emulsion is either not chemically sensitized or only slightly sensitized. The photographic material and its use includes both producing black and white and colored photographic images and has high sensitivity to light and by fogging development yields pure image whites.

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Inventors: Klotzer, Sieghart (Cologne, DT)
Moisar, Erik (Cologne, DT)

Application Number: 442614
Filing Date: 1974-02-14
Publication_date: 1976-01-27
Assignee: Agfa-Gevaert Aktiengesellschaft (Leverkusen-Bayerwerk, DT)
Primary Class(es): 430/409 430/567, 430/599
Other Classes:
US Patent Ref:

2592250	Mar, 1949	Davey et al.	96/114.
3206313	Sep, 1965	Porter et al.	96/107.
3317322	May, 1967	Porter et al.	96/107.
3367778	Feb, 1968	Berriman	96/108.
3586505	Jun, 1971	Ridgway	96/107.
3761266	Sep, 1973	Milton	96/107.

Other Refs:
Primary Examiner: Louie, Jr., Won H.
Assistant Examiner:
Attorney: Connolly and Hutz