GB1260722A - Improvements in physical development in an image reproduction process - Google Patents

Abstract

1,260,722. Physical development of non-silver images. MINNESOTA MINING & MFG CO. Jan. 10, 1969 [Jan. 11, 1968; Feb.7, 1968], No. 1734/69. Heading G2C. [Also in Division C7] An image reproduction process comprises exposing a photo-sensitive layer of a photosensitive medium to a light image, the said layer comprising a composition which upon light exposure directly generates nuclei of a metal which is more noble than silver (i.e. metals which are less readily oxidized than silver) and is catalytic to the electroless deposition of a non-noble free metal, and providing non-noble free metal selectively on these nuclei by electroless deposition to provide a visible print of the light image, the photo-sensitive layer having incorporated therein or in contact therewith prior to exposure to the light image at least one salt of bismuth, antimony, lead, tin or, when the nuclei more noble than silver are not formed from a gold salt, silver or gold and/or after exposure the non-noble free metal in the presence of at least one salt of bismuth, antimony, lead, tin, titanium, tungsten or chromium being selectively provided on the nuclei. The non-noble free metal is preferably nickel and/or cobalt, and the metal which is more noble than silver is preferably palladium. The salts referred to above may be gold chloride, silver nitrate, bismuth trichloride, antimony trichloride, lead acetate, tin tetrachloride, sodium tungstate, chromium chloride or chromium fluoride. In the examples the light-sensitive entity is ferric ammonium oxalate/palladium chloride or ferric ammonium oxalate/ammonium chloropalladate. This process provides a continuous tone image reproduction.