Product Code Database
Platinum prints, also called platinotypes, are photographic prints made by a monochrome printing process involving platinum.
Platinum tones range from warm black, to reddish brown, to expanded mid-tone grays that are unobtainable in silver prints.
Unlike the silver print process, platinum lies on the paper surface, while silver lies in a gelatin or Albumen print emulsion that coats the paper. As a result, since no gelatin emulsion is used, the final platinum image is absolutely matte with a deposit of platinum (and/or palladium, its sister element which is also used in most platinum photographs) absorbed slightly into the paper.
Platinum prints are the most durable of all photographic processes. The platinum group metals are very stable against chemical reactions that might degrade the print—even more stable than gold. It is estimated that a platinum image, properly made, can last thousands of years. Some of the desirable characteristics of a platinum print include:
In 1832, Englishmen John Herschel and Robert Hunt conducted their own experiments, further refining the chemistry of the process. In 1844, in his book Researches on Light, Hunt recorded the first known description of anyone employing platinum to make a photographic print. However, although he tried several different combinations of chemicals with platinum, none of them succeeded in producing any permanency in the image. All of his prints faded after several months.
Over the next decade, Hunt noted that platinum prints he had left in the dark faded very slowly but gradually resumed their original density, and had also shifted from a negative to a positive image, eventually becoming permanent.
By the early 1850s, however, other more reliable photographic processes, such as salt print and albumen print printing, had been developed and were beginning to be widely used. Those scientists who had previously conducted research on platinum lost interest in the process as other methods became more commercially viable. The only major advances in platinum research reported during that decade were made independently by C.J. Burnett and Lyonel Clark of Great Britain. In 1859, Burnett published an article in the British Journal of Photography describing his use of sodium chloroplatinate as a fixing agent. His modification of the platinum printing process resulted in prints that were permanent enough that he could exhibit them in public. That same year, Clark also exhibited prints made using a slightly different process.
Willis introduced the "hot bath" method where a mixture of ferric oxalate and potassium chloroplatinate are coated onto paper which is then exposed through a negative and developed in a warm solution of potassium oxalate.
Willis quickly countered this advance by obtaining two more patents in 1888 for cold-bath processes. By adding more platinum to the developing process, he produced prints that had dense brown-black shadows rather than the lighter browns that were the best that previous processes could produce. While much more aesthetically pleasing, prints developed by this process were difficult to produce reliably.
Four years later, Willis began manufacturing a platinum paper that was designed for the cold-bath process, and this became the standard for the rest of the decade. The business he started in 1880, called the Platinotype Company, rapidly expanded, and soon he was selling his paper throughout Europe and in the United States. By 1906, his company had sales totaling US $273,715 ($ in 2009 dollars), a significant amount at that time.
Seeing the skyrocketing demand for platinum paper, the Eastman Kodak Company in Rochester, New York, tried to develop its own line of paper starting in 1901, but they could not duplicate the quality of Willis's product. Kodak then tried to buy Willis's company but was not able to come to an agreement. Kodak instead bought the relatively new company of Joseph Di Nunzio who had recently developed his own brand of platinum paper comparable to Willis's, which he sold under the name of "Angelo". Kodak continued to sell this paper for several years before it was eventually discontinued.
When Willis began marketing his paper, platinum was relatively cheap. By 1907, platinum had become 52 times more expensive than silver. Eastman Kodak and most other producers stopped fabrication of the paper in 1916. Russia controlled 90% of the world platinum supply in World War I and all available platinum was used in the war effort. Nevertheless, platinum paper has continued in use until the present, interrupted only by the world wars.
Beginning in 1964, Irving Penn began experimenting with platinum printing. Penn had spent his career up to that point making photographs that were seen almost exclusively in reproduction within the glossy pages of magazines and in his pivotal 1960 book Moments Preserved. Penn set himself the challenge of producing photographic prints that would surpass the technical limitations of reprographic media and deliver a deeper visual experience. He was drawn to the antiquated platinum process for its long grayscale – its ability to display a seemingly infinite array of gradations between pure white and absolute black.
The platinum process requires direct contact with the negative, without enlargement, so Penn first needed to create flawless negatives the same size as the desired print. He then hand-coated paper with platinum emulsion. When dry, the paper was sandwiched with the negative and exposed to light before processing. Rigorous experimentation revealed that recoating a print with a secondary emulsion and making a second or third exposure of the same image on a single sheet of paper yielded prints of greater depth and subtlety. Penn solved the problem of aligning and re-aligning the negative and the print surface over multiple exposures by borrowing a technique from the graphic arts: he mounted his paper on a sheet of aluminum with a series of registration guides along the top edge. Penn was guarded about the preparation of his emulsions and his precise formulations varied considerably. He frequently introduced palladium and iron salts into his coatings to achieve desired effects.
Characteristics of a palladium print, compared to a platinum print:
By varying the amount of platinum versus palladium and the addition of oxidizing chemicals such as hydrogen peroxide and potassium dichromate or potassium chlorate, the contrast and "color" of the final image can be modified. Because of the non-uniformity of the coating and mixing phases of the process, no two prints are exactly the same.
In 2002, working from research done by Howard Efner and Richard Sullivan, Dick Arentz formulated the methodology for using sodium chloroplatinate as a contrast control agent. Richard Sullivan coined the term Na2 and began to sell a 20% solution through Bostick and Sullivan. Arentz found that, since it is a platinum compound (sodium chloroplatinATE), it does not work with platinum prints (potassium chloroplatinITE). It does, however, shorten the scale of a pure palladium print. When minute quantities of sodium chloroplatinate are added to the palladium salt/ferric oxalate emulsion it produces the high-contrast prints needed for thin negatives, but does not exhibit the granularity found when using traditional chlorates. A palladium print made with potassium chlorate will take on a warm, sepia tone. The same print using sodium chloroplatinate will have cooler tones similar to those of a platinum/palladium print.
The inherent low sensitivity of the process occurs because the ferric oxalate is sensitive to ultraviolet light only, thus specialized light sources must be used and exposure times are many times greater than those used in silver-based photographic processes.
Due to the unavailability of pre-coated sensitized paper, all platinum/palladium printing is done on paper coated by the printer. The light sensitive chemicals are mixed from powdered basic chemicals, or some commercially available solutions, then hand applied with a brush or a cylindrical "pusher".
Many artists achieve varying effects by choosing different papers for different surface characteristics, including vellum, 100% cotton rag, silk, and rice, among others. On the collecting market, platinum prints often sell for many times what a similar silver-gelatin print would bring.
|
|
