Berchtold discovered one of the first successful methods of achieving halftones in the intaglio reproduction of photographs. While William Henry Fox-Talbot was experimenting with mesh screens in England, Berchtold was finding success in Austria etching glass plates with narrow, parallel lines. By 1857 Berchtold had produced the first line screen, and, although crude, Berchtold’s tests are considered one of the earliest breakthroughs in achieving continuous tone in photographic reproductions. To create an image, as described in his 1857 patent, Berchtold exposed a glass plate three times. For the first exposure, the image negative was in direct contact with a plate. Next, Berchtold exposed the image through a fluted pane of glass with etched parallel lines. For the last exposure, Berchtold rotated the pane of glass 90 degrees to create a grid pattern with the etched lines. Berchtold’s line screen can retrospectively be considered futuristic in its adaptation of a mathematically-achieved continuous tone, and can be compared to today’s technical standards of image resolution in terms of pixels, dots and line per inch. Despite his important contributions to the field, Berchtold’s line screen process was not received with due excitement when submitted to the Luynes competition. Berchtold died during the competition in 1859, and many consider his process to have died with him. After Berchtold, screen processes in France did not develop until the 1870s, and widespread industrial use of the screens did not catch on until the 1890s.
Frizot, Michael. New History of Photography. Place of publication not identified: Pajerski, 1999. Printv P. 229
Lewis, Jacob W. Charles Negre in Pursuit of the Photographic. , 2012.
Marbot, Bernard. Une Invention Du Xixe Siècle, Expression Et Technique, La Photographie: Collections De La Société Française De Photographie, Paris, [12 Juin-14 Août] 1976,
Bibliothèque Nationale / [catalogue Par Bernard Marbot ; Préface Par Georges Le Rider]. Paris: Bibliothèque nationale, 1976. no. 286.