| 摘要 |
1,030,217. Photographic processes using photochromic materials. NATIONAL CASH REGISTER CO. Dec. 21, 1964 [Jan. 16, 1964], No. 51792/64. Heading G2C. Thermally stabilized images are produced in a layer of one or more non-crystalline, photochromic spiropyran compounds by imagewise exposing the material to ultra-violet radiation and treating the layer before or after exposure with a hydrogen halide or sulphur dioxide vapour to form an acid complex. Preferably the imaged layer is heated to drive off the acid vapour from the non-image areas. The yellow image may be converted to a blue image by treating the layer with alkali but if the layer, is then re-exposed to a different image and treated with acid vapour two yellow images are produced. Multi-colour images may be produced by image-wise exposing a benzoindolinospiropyran to ultra-violet and treating with hydrochloric acid vapour, removing the background areas with toluene, recoating with a different spiropyran, image-wise exposing and treating with hydrogen chloride and then with ammonia to give one purple and one blue image. The layer may be exposed to hydrogen halide vapours before or after image-wise exposure but to sulphur dioxide vapours only after image-wise exposure. |
