Examples of Salted Paper Prints
Image discoloration and fading
Paper fibers visible
Matte surface sheen
Common Use Dates: 1840-1855
Alternate Names: Salt Print, Calotype Positive Print, Crystalotype
Mistaken For: Albumen Print, Matte Albumen, Matte Gelatin POP
Process Family(s): Photographic, Silver, Printing-out
Salted paper is a printing out process based on the light sensitivity of silver chloride, which is hand applied directly onto a paper support.
Salted paper prints were created by first floating a sheet of paper in a solution of sodium chloride. Once the sheet was dry, it was floated or brushed with a solution of silver nitrate. The resulting chemical reaction formed light sensitive silver chloride compounds. The sensitized paper had to be printed immediately for optimal results. The paper was contact printed with a negative and exposed with ultraviolet light. Though artificial light is available for use today, the traditional source of ultraviolet light in the mid-19th century was sunshine. Once the desired exposure was achieved, the print was then washed, toned, washed again, fixed with sodium thiosulfate (“hypo”), and placed in a final wash. Once dry, prints were flattened and could be mounted to a secondary support, placed in window mat frames, books, or albums for display.
Toning of salted paper prints was common and a number of techniques were used, from heat to the later use of sodium thiosulfate (sulfur) and gold chloride. Untoned, finished prints were a warm red, while sulfur and gold toning changed them to a purplish brown. Preference for the color achieved through toning led to experimentation with different compounds. The use of sodium thiosulfate as a toning agent as well as a fixing agent was common during the beginning of the salted paper era, but stability issues led to the addition of gold chloride combined with sodium thiosulfate, known as sel d’or toning. Stability problems persisted, and it was eventually replaced by the use of gold chloride alone in the mid-1850s as well as other Nobel metal toners in later years. Although toning changed the overall hue, the choice of paper and the amount and type of sizing in it ultimately had the biggest effect on the final print color. The use of high-quality, pure cellulose (cotton) papers was desirable for making salted paper prints, as the use of lesser-quality papers (such as those made from wood) would frequently contain imperfections that could contaminate the prints and/or react to chemicals used and lead to deterioration.
The salted paper process was first developed by William Henry Fox Talbot circa 1834-1835. The technique was publicized in 1839 and remained in use until approximately 1855, when aesthetic tastes shifted toward the highly detailed, glossy appearance of albumen prints. Talbot first used the salted paper process to create photogenic drawings (photograms). Objects such as feathers, plants, and lace were arranged on sensitized paper and placed in sunlight. After exposure and processing, the print produced was a negative image, which was created by blocking exposure of the sensitized paper to light with the arranged objects. While working on the salted paper process, Talbot also developed the calotype, or paper negative. Though the process was similar to salted paper, it differed somewhat in both the chemistry (a combination of silver iodide and both acetic and gallic acid) and process (developed-out rather than printed-out). The resulting calotypes were negative images, which could then be used with sensitized salted paper to create positive prints, and the basic salted paper process was established.
Improvements to the technique were made in the following years, including toning with gold chloride and the use of sodium thiosulfate (“hypo”) as a fixer at the suggestion of Sir John F.W. Herschel in 1839. Up until that point, Talbot had been using a strong salting solution to stabilize prints. The method worked short-term, but not as a permanent fixer as the salting solution only reduced light sensitivity rather than stopping it all together. Talbot’s switch to sodium thiosulfate fixer was the final piece of information lacking in the photographic process, and from that point forward the print permanence was greatly improved. Changes in negatives were also developed, from the application of wax for heightened transparency to the use of wet plate collodion negatives to improve sharpness and detail beginning in the early 1850s. Unknown to Talbot at the time, the negative-positive technique he developed was to become the primary method of photographic printing until the end of the 20th century.
Salted paper printing was an extremely popular form of photography even though it was in use for a relatively short period of time. Unlike the processing of daguerreotypes, which needed a range of special equipment and dangerous chemicals for production, the salted paper technique was simpler in both respects. Another advantage over daguerreotypes was that the negative-positive process allowed for many copies to be made from one negative. The introduction of mass-produced, un-sensitized salted papers in the 1850s further simplified the process, and it remained popular until albumen printing became prevalent around 1855. Though there was a brief resurgence of interest in the salted paper process at the turn of the 20th century, salted papers (including albumen papers) were completely out of commercial production by the end of the 1920s. In recent years, salted paper printing has experienced a revival yet again due to increased interest in historic processes among photographers and artists.