The history of three-color photography (1925)

Subtractive Processes. V 437 washing. Klein suggested that it would be possible to utilize the sensitiveness of the silver halides in the bleach-out process, and pointed out that there are several dyes, which, when compounded with silver salts, acquire the property of bleaching in light ; this bleaching effect, when once initiated, progressed in the dark by the aid of sodium sulfite or bisulfite baths. He cited as example orthochrom T, and stated that there were also blue, yellow and green dyes with similar properties. M. Schneider57 reported a rather curious experience. Having prepared in a test tube a mixture of collodion, eosin, methylen blue and auramin, all Hoechst dyes, a considerable quantity of thiosinamin was added with a few drops of sulfuric acid, and the mixture, which had a blackish color, became gradually green and then yellow. As the yellow did not disappear, a new mixture was made without the auramin, and when treated in the same way became colorless. This was coated on baryta paper, exposed for 30 seconds to sunlight under a colored transparency, and the outlines of the red and blue colors were visible after exposure. The prints were then developed with hot ammoniacal water, the blues, the reds and violets were perfectly reproduced and the rest of the image remained white. The action of light, therefore, had destroyed the complementary colors and retained those corresponding to the original. It was not found possible to obtain a yellow that would answer to this treatment. J. Gaedicke, the editor of the Photographisches Wochenblatt, in which this note appeared, stated that another experimenter, who desired to remain anonymous, had tried this process without results. 1. D.R.P. 227,129; 309,376; 388,512; 390,163; 390,165, 1909; Handbuch, 4, III, 383; Jahrbuch, 1909, 23, 416; 1910, 14, 166, 542, 613; 1911, 25, 545; Phot. Rund. 1909, 23, 157, 257; 1910, 24, 151, 613; Phot. Korr. 1907, 44, 74; Phot. Chron. 1910, 17, 46, 59, 493; abst. C. A. 1909, 3, 2,911; 1910, 4, 1,137, 2,240; E.P. 7,932, 1909; Brit. J. Phot. 1910, 57, 28; "Die Praxis des Askaudrucks," 1910. In D.R.P. 312,657, 1918; abst. J. S. C. I. 1919, 38, 878A, alcohol and acetone were added to the developer. Cf. R. T. Wall, E.P. 775, 1882; Phot. News, 1909, 53, 589; Jahrbuch, 1909, 23, 417. P. van Duyse, Phot. Moderne, 1925, 3, 28. 2. D.R.P. 211,329, 1908; abst. C. A. 1910, 4, 2,419; Jahrbuch, 1910, 24, 613; 1911, 25, 543; Phot. Chron. 1910, 17, 59. Cf. D.R.P. 390,163, 1922; abst. Phot. Ind. 1924, 500. 3. D.R.P. 40,774, 1887; Silbermann, 1, 219. 4. D.R.P. 62,662, 1891 ; Silbermann, 1, 220. 5. Zts. ang. Chem. 1890, 3, 451; Phot. Annual, 1891, 158. 6. Compt. rend. 1912, 155, 280; Brit. J. Phot. 1912, 59, 731; abst. C. A. 1912, 6, 3,371. 7. D.R.P. 53,455, 1889; Silbermann, 1, 216; Phot. Mitt. 1890, 17, 187; 1891, 18, 187; Phot. News, 1891, 36, 98; Phot. Annual, 1891, 98; Jahrbuch, 1891, 5, 529; Handbuch, 1899, 4, IV, 562; Bull. Soc. Ind. Mulhouse, 1890, 60, 307; Fabre, "Traite Encycl." Supp. A. 286. K. Noack, Phot. Korr. 1898, 35, 633; Jahrbuch, 1900, 14, 215; Liesegang's Phot. Almanach, 1899, 20, 17; Brit. J. Phot. 1898, 45, 822 used Feertype for the red print, with lead chromate for the yellow and cyanotype for the blue. 8. E.P. 7,453, 1890; Brit. J. Phot. 1890, 37, 657, 686; 1891, 38, 57, 71, 331, 453. 456; Brit. J. Almanac, 1892, 535; Phot. News, 1890, 34, 701, 707; abst. J. S. C. I. 1890, 9, 1001; Phot. Annual. 1891, 98; D.R.P. 56,606, 1890; Silbermann, 1, 216; Jahrbuch, 1892, 6, 458; Handbuch, 1899, 4, IV, 563; Phot. Times, 1890, 20, 568, 1891, 21, 30; Bull. Soc. franc;. Phot. 1891, 38, 24, 107; F.P. 207,963;