|The following is excerpted from Osterman, Mark "Some Important Dates in the Evolution of Gelatin and Collodion-Chloride Printing-Out Papers." George Eastman House, Rochester, NY, 2006.|
* 1802: Thomas Wedgwood makes printed out images on paper sensitized with silver nitrate and sodium chloride but is unable to remove the unexposed silver halides.
* 1819: Sir John Herschel identifies "hyposulfites" and their solvent effect on silver chloride.
* 1839: Louis Daguerre publishes the use of sodium thiosulfate as a fixing agent in his manual. Fox Talbot discloses his use of sodium thiosulfate to fix silver chloride prints.
* 1851: F. Scott Archer introduces the wet-plate collodion process for negatives. The original technique was to make the negative image on a glass plate, then transfer the image bearing collodion film onto a secondary paper support for printing. Archer's intent was to improve the calotype process. Soon after it's introduction the process evolved to use the glass plate as the final support.
1855: Dr. Moittessier makes prints by transferring positive collodion images from a glass plate onto a secondary paper support.
* 1853-1861: Marc Gaudin introduces the concept of a collodion emulsion containing both the halide and silver. He also suggests gelatin and albumen as a possible binder for emulsions. In 1861 he coins the term "photogene" for collodion emulsions. There is no evidence that he ever manufactured collodion papers commercially.
1864: William Bolton and J.B. Sayce introduce collodion-bromide emulsion for physically developed negatives.
* 1865: G. Warton Simpson makes prints using a collodion-chloride emulsion though it is not commercially produced.
1860s-1880s: Collodion emulsions, both chloride and bromide, are used for the production of milk glass positives (aka opaltypes) and lantern slides.
* 1866: Martinez Sanchez and Jean Laurent introduce baryta coating on photographic paper and Leptographic paper, a collodion-chloride printing-out paper. They manufacture hand coated Leptographic paper from 1866-1869.
1867: J.B. Obernetter begins production of hand coated collodion-chloride printing-out paper.
1868: W.H. Harrison invents a gelatin bromide emulsion for chemical development.
1869: Adolf Ost suggests the use of citric acid for preserving silver-chloride papers.
1873: Peter Mawdsley makes gelatin-bromide developed-out papers.
1881: J.M. Eder and Giuseppe Pizzighelli make gelatin-chloride emulsion for development. Not to be confused with printed-out emulsions.
* 1882: Wm. De Abney introduces gelatin-chloride emulsion for printed-out photographic paper.
* 1884: George Eastman introduces the first negative roll film, a gelatin-bromide emulsion on paper support, and the first machine for continuous coating emulsions on paper.
* 1884: J.B Obernetter and P.E. Liesegang independently introduce mechanical coating of collodion chloride printing-out paper. Obernetter coins the name Aristo for his product.
* 1885: Ashman and Offord introduce self-toning collodion-chloride printing-out paper containing gold chloride. Self toning emulsions are eventually produced by all makers of gelatin and collodion printing-out papers.
1889: The Aristo Company (Jamestown, NY) manufactures collodion-chloride Aristo paper. By
1891 both gelatin and collodion papers were produced by the Aristo Company. American Aristo was the specific product name for the collodion-chloride papers while gelatin-chloride papers were simply called, Aristo.
* 1891: Britannia Works Co. introduces Ilford P.O.P., a gelatin-chloride printing-out paper. While specific to the Ilford product, the term printing-out paper (and the initials P.O.P.) is eventually used as a generic term for all silver-chloride printing-out papers including salt, albumen, gelatin and collodion.
1893: Leo Baekeland invents Velox, a contact printed gelatin-chloride developed-out paper; popularly known as gaslight paper.
* 1901: Gevaert manufactures matte collodion-chloride printing-out paper. These papers were toned with either gold or gold and platinum and were available as self-toning papers as well. Other companies follow suit with similar papers beginning the decline of glossy finish printing-out papers and the burnishing of mounted prints. Glossy collodion papers fall from fashion by World War I.
Matte collodion-chloride printing-out papers were used as late as the 1930s in Europe. Gelatinchloride printing-out papers on the other hand have been available continuously since their introduction. They are still being made by the Kentmere Company and sold through the Chicago Albumen Works as of January, 2006. Over the years gelatin-chloride printing-out papers have been marketed as POP, Aristo, Solio, and studio proof paper to name a few. Gelatin-chloride printing-out papers were overtaken by the popularity of developing-out papers by the 1920s, but continued to be manufactured for many years as a commercial proofing paper. Today there is renewed interest in fully processed gelatin-chloride printing-out papers by fine arts photographers and those seeking a means to print from historic glass negatives without the trouble of making albumen paper.