It is a long-standing objective that color photographic origination materials maximize the overall response to light while maintaining the lowest possible granularity. Increased photographic sensitivity to light (commonly referred to as photographic speed) allows for improved images captured under low light conditions or improved details in the shadowed regions of the image. In general, the overall light sensitivity provided by the light sensitive silver halide emulsions in such systems is determined by the size of the emulsions. Larger emulsions capture more light. Large silver grains or silver halide grains having high iodide content, generally develop at a slower rate than emulsions having smaller grains or lower iodide content. Upon development, the captured light is ultimately converted into dye deposits which constitute the reproduced image. However, the granularity expressed by these dye deposits is directly proportional to the grain size of the silver halide emulsion. Thus, larger silver halide emulsion grains have higher sensitivity to light but also tend to have higher granularity in the reproduced image. It has been a long-standing problem to provide materials which maximize the response to light of a silver halide emulsion for any given grain size.
Customers continue to demand faster products with improved photographic performance. The sensitivity of widely used silver halide photographic materials has increased over the years from an ISO sensitivity of 100 to an ISO sensitivity of greater than 1000. Methods to accelerate development of exposed silver halide grains, which enable higher photographic response with smaller silver halide grains and/or lower granularity, have been realized. For example, U.S. Pat. No. 4,912,025 describes the release of electron transfer agents (ETAs) for development acceleration without a concomitant granularity and fog increase. These type of compounds are commonly referred to as electron transfer agent releasing couplers or ETARCs. More recently, U.S. Pat. No. 5,605,786 describes a method of imagewise release of an ETA where an --O--CO--(T).sub.n --(ETA) group is attached at the coupling-off site of the ETARC. In addition, U.S. Pat. No. 4,859,578 describes 1-arly-3-pyrazolidinone ETAs in combination with a SMRC.
The inventors herein have found that the disadvantage of ETARC compounds used previously is that once released, the ETA fragment migrates out of the layer in which it was coated. This undesired movement of the ETA creates unwanted dye density in the adjacent layer as a function of development of the primary layer and is commonly referred to as wrong way interimage. Wrong way interimage can lead to inaccurate or undesirable color reproduction of the recorded image. The photographic industry continues to need new tools to increase speed and minimize granularity without causing other deleterious consequences.