Image forming composition and elements with Co(III) complex, conjugated pi bonding compounds and photoreductant

摘要

An image-forming element is disclosed comprised of a support and a coating thereon containing a cobalt(III)complex and a compound containing a conjugated pi bonding system capable of forming at least a bidentate chelate with cobalt(III). The coating is predominantly free of anions which will form conjugate acids by deprotonation of a cobalt(II)complex containing the chelating compound. In one preferred form the image-forming element is radiation-sensitive. In this form the image-forming element can contain a photoactivator capable of initiating reduction of the cobalt(III)complex. An imaging process is disclosed in which the coating is exposed to actinic radiation to produce an image. Images can be recorded directly within the image-forming coating or in a separate image-recording element or layer by use of the residual cobalt(III)complex or by use of one or more of the reaction products produced by exposure. By using the ammonia liberated from ammine ligand containing cobalt(III)complexes on exposure in combination with imagewise and uniform exposures, positive or negative images can be formed in diazo image-recording layers or elements associated with the image-forming coating.