GB1232774A - - Google Patents

Abstract

1,232,774. Photographic silver salt diffusion transfer process; processing compositions. POLAROID CORP. Jan.22, 1969, [Jan.22, 1968], No.3617/69. Heading G2C. A photographic processing composition comprise a liquid vehicle having dissolved therein a silver halide developing agent and, as a silver halide solvent, at least one organic derivative of a trihydride of trivalent phosphones, arsenic or antimony, said devivative being capable of reacting with silver halide to form a complex silver salt that is soluble in said vehicle. The derivative preferably has the general formula Y m -X-R (3-m ) wherein Y represents a group of the formula - Z-XR 2 in which Z is a divalent organic radical; each radical X is trivalent P, As or Sb; each radical R is H or a monovalent organic radical; m is 0 or 1, and not more than two of the radicals R are H when M is 0. In the examples tris- (paratrydroxy-phenyl) phosphine is used. The liquid vehicle is usually water but it may be an organic liquid, preferably a volatile organic liquid, or a mixture of water and an organic liquid. The acidity and alkalinity of this processing composition may range from a hydrogen ion concentration of IN to a hydroxyl ion concentration of SN. The present processing composition give good transfer image in the silver salt diffusion transfer process. The derivatives of P, As or Sb used in this composition are oxidized in air to give pale or colourless residue which is not deleterious to the transfer image and are effective silver halide complexing agents under less alkaline conditions than normally employed.