GB1497452A - Radiation-sensitive materials and methods of image formation - Google Patents

Abstract

1497452 Photo-sensitive material EASTMAN KODAK CO 15 April 1975 [15 April 1974] 15495/75 Heading G2C Photo-sensitive material comprises a cobalt III complex free of sensitizable anions and a photoreductant capable of forming a redox couple with the complex on exposure to radiation of wavelength greater than 300 nm. The redox reaction, which may be assisted by heating at 80-150‹C, releases at least one ligand, e.g. ammonia. The complex may be decompozable by the released liquid. The complex and reductant may be in the same or separate layers. The material preferably also contains a reductant adjuvant which is a source of hydrogen atoms (necessary when the photoreductant lacks an internal hydrogen source) and a binder (which may be a reductant adjuvant). The complex, reductant and adjuvant may be applied to a support in a common solvent. On exposure, an image may be produced in a separate image recording material, e.g. one which is visibly responsive to ammonia. The image-recording material may be contacted with the photo-sensitive material during exposure (preferably through a separation layer) or, when the redox reaction requires heat for completion, after exposure. The image-recording material may be photo-sensitive (to visible or UV light). An image may, alternatively be produced in the photo-sensitive material, e.g. by reaction of the non-reduced complex with a leuco dye or colour developer, or by reaction of the reduced complex with a compound containing a thioamide functional group. A multi-layer material may produce a multi-colour image. The photoreductant may be a disulphide, diazoanthrone, diazophenanthrone, aromatic carbazide, aromatic azide, diazonium salt, or aromatic diazosulphonate. Specific Examples of complexes, reductants, adjuvants, binders and imaging materials are given.