PHOTOGRAPHIC ELEMENT CONTAINING A LAYER OF PHYSICAL DEVELOPMENT NUCLEI LESS THAN TWO MICRONS IN THICKNESS AND A DEVELOPMENT ACTIVATOR

摘要

A physical developer activator material such as a material which reacts with the oxidized form of the reducing agent component of a physical developer is added to a photographic element comprising physical development nuclei or a photosensitive material capable of generating such nuclei. A preferred physical development activator material is an organic acid or a salt of an organic acid such as ammonium tartrate. This photographic element is utilized in a process comprising forming an image of physical development nuclei and then contacting the medium with a unitary physical developer comprising a solution of metal ions and a reducing agent for these metal ions. The photographic element of this invention is also utilized in a printing process comprising forming an image pattern of physical development nuclei in the photographic element, contacting the element with a unitary physical developer and then using the thus imaged element as a printing plate. The addition of the physical developer activator in the element used in this printing process improves the printing capability of the highlight dots or fine detail areas of the final printing plate. A preferred photographic element is one wherein the layer of physical development nuclei or photosensitive material capable of generating such nuclei has a thickness of less than about 2 microns. Preferred photosensitive materials useful in these processes are silver halide, titanium dioxide, zinc oxide, and tin oxide.