pyro Photogr.
(ˈpaɪərəʊ)
Abbreviation of pyrogallic acid or pyrogallol, extensively used as a developing agent. Often attrib. and in Comb., as in pyro-developer, pyro-solution, etc.
| 1879 Cassell's Techn. Educ. III. 294 The proper developing agent for collodio-bromide plates is..known as the alkaline pyro-developer. 1885 C. G. W. Lock Workshop Receipts Ser. iv. 376/2 Take enough of the pyro solution in your developing tray to well cover the plate. 1892 Photogr. Ann. II. 44 Pyro and other photo chemicals are violent poisons. 1893 Brit. Jrnl. Photogr. XL. 747 Pyro is used in conjunction with sodium sulphate. 1905 Westm. Gaz. 5 Aug. 14/2 One of the chief merits of the pyro-developed negative. |
b. Comb., indicating a mixture of pyrogallic acid with another substance, as a developer: e.g. pyro-ammonia, pyro-lime, pyro-metol, pyro-potash, pyro-soda; pyro-carbonate, pyrogallic acid with carbonate of soda.
| 1885 C. G. W. Lock Workshop Receipts Ser. iv. 357/1 The pyro-lime developer becomes violet and brown in use. 1890 Anthony's Photogr. Bull. III. 108 Now a word about developers. I have tried them all... Ferrous oxalate pyro-soda, pyro-potash, hydroquinone, etc. Ibid. 312, I have developed a good many dozens of exposures, and with pyro-ammonia or pyro-carbonate I have not yet got an unevenly developed film. 1907 Westm. Gaz. 2 Mar. 18/2 A green-brown or brown-black colour, such as is given by a pyro-metol developer or pyro-soda not too heavily dosed with sulphite. |