1. Field of the Invention
This invention relates to photography, and more particularly, it relates to compositions and processes useful in the development of photosensitive silver halide emulsions.
2. Description of the Prior Art
In recent years, there has been a growing interest in heterocyclic developing agents, i.e., developers containing a heterocyclic ring as part of their structure. Some of these developing agents have the conventional hydroxyl or amino developing groups substituted on adjacent carbon atoms of a heterocyclic ring to provide structures similar to those of the developing agents in the aliphatic and aromatic series. Still other heterocylic developing agents have one of the functional developing groups included as part of the heterocyclic ring. Illustrative developing agents of the latter type include 1-phenyl-3-pyrazolidone and its 4,4-dialkyl derivatives which form the subject matter of U.S. Pat. No. 2,289,367 and 2,772,282, respectively, and 1-phenyl-4-amino-5-pyrazolones which form the subject matter of U.S. Pat. No. 2,895,825.
The present invention is concerned with the use of certain 4-hydroxy pyrazoles as silver halide developing agents.