Eastman-kodak Company

Marian S Henry

Richard L Parton

Kenneth Joseph Reed

Myra T Olm

Steven G Link

David A Stegman

Harry J Price

Pamela M Ferguson

John E Keevert

Woodrow G McDugle, Jr

Alfred P Marchetti

Thomas R Dobles

Douglas L Oehlbeck

Alton L Chitty

Karen L Pond

Sandra M Finn

Nona Veith Spitzner

Ward K Darron

A photographic element having a silver halide emulsion spectrally sensitized to blue light by a dye of formula (I) to have a maximum blue sensitivity at less than 485 nm. The dye allows the element to have good color reproduction while still providing good speed response despite the shorter blue sensitivity. Formula (I) is: ##STR1## wherein: X and X' each independently represent the atoms necessary to complete a thiazole, benzothiazole, naphthothiazole, oxazole, benzoxazole, naphthoxazole, selenazole, benzoselenazole, naphthoselenazole, imidazole, benzimidazole, or naphtho-imidazole, and X may be further substituted and X' substituted or unsubstituted;

Blue sensitizing dyes with heterocyclic substituents

A process for controlling the silver halide grain-to-grain distribution of a variable contrast dye in a light sensitive silver halide emulsion layer of a variable contrast photographic element, and thereby adjusting the low contrast characteristic curve of the element, is disclosed comprising the process steps of adding a green variable contrast sensitizing dye of the following formula (I) to a silver halide emulsion for a variable contrast photographic element, adding a blue sensitizing dye of the following formula (II) to the same silver halide emulsion, and coating the emulsion on a support. In the process, the green and blue sensitizing dyes are added to the emulsion at substantially the same time, and the green dye is added in an amount less than that required to impart maximum sensitivity to all of the silver halide in the emulsion. ##STR1## In formula (I), R.sup.1, R.sup.2, R.sup.6 and R.sup.7 each independently represent hydrogen, halogen, hydroxy, or substituted or unsubstituted alkyl, alkenyl, alkoxy, alkylamino, alkylthio, aryl, aryloxy, arylamino or arylthio. R.sup.3, R.sup.4 and R.sup.5 each independently represent substituted or unsubstituted alkyl or aryl. X represents a counterion as needed to balance the charge of the molecule. In formula (II), Z represents the atoms necessary to complete an optionally further substituted five- or six-membered heterocyclic ring, R.sup.8 represents substituted or unsubstituted alkyl or aryl, and R.sup.9 represents hydrogen, substituted or unsubstituted alkyl or aryl, or a heterocycle.

Method for controlling characteristics curve shape for variable contrast

A method for the reproducible production of nonuniform distributions of polymolecular association clusters, each of the clusters comprising a plurality of a species A in association with a single species B, is disclosed. Species A is preferably a photographic dye and Species B is preferably a silver halide particle. The method comprises: (a) mixing a suspension of particles of species B in a vessel; (b) flowing a portion of the suspension through an isolated reaction zone; (c) introducing species A into the isolated reaction zone; and (d) returning the portion of the suspension including the introduced species A to the vessel. In another aspect, the invention relates to an apparatus for carrying out the foregoing process.

Process and apparatus for reproducible production of non-uniform product

Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure internally containing a carbonyl coordination ligand and a transition metal chosen from groups 8 and 9 of the periodic table of elements.

Photographic emulsions containing internally modified silver halide

Growing community of inventors

Rochester, NY, United States of America

Marian S Henry