![]() William Willis was the first to patent the platinotype process in 1873 (British Patent No. That same year, Clark also exhibited prints made using a slightly different process. His modification of the platinum printing process resulted in prints that were permanent enough that he could exhibit them in public. In 1859, Burnett published an article in the British Journal of Photography describing his use of sodium chloroplatinate as a fixing agent. Burnett and Lyonel Clark of Great Britain. The only major advances in platinum research reported during that decade were made independently by C.J. Those scientists who had previously conducted research on platinum lost interest in the process as other methods became more commercially viable. īy the early 1850s, however, other more reliable photographic processes, such as salt and albumen printing, had been developed and were beginning to be widely used. 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. All of his prints faded after several months. However, although he tried several different combinations of chemicals with platinum, none of them succeeded in producing any permanency in the image. In 1844, in his book Researches on Light, Hunt recorded the first known description of anyone employing platinum to make a photographic print. In 1832, Englishmen Sir John Herschel and Robert Hunt conducted their own experiments, further refining the chemistry of the process. The combination of these two metals remains the basis of the platinotype process in use today. Through experimentation, he eventually found that ferric oxalate was a highly-effective enhancer. The following year, his countryman, Johann Wolfgang Dobereiner, determined that the action of light on platinum was quite weak, but that perhaps something could be combined with platinum to increase its sensitivity. The first person to have recorded observing the action of light rays on platinum was Ferdinand Gehlen of Germany in 1830. 6 Notable photographers using the technique.This somewhat misleading abbreviation was coined by Richard Sullivan of Bostick & Sullivan, one of the principal suppliers of chemistry and printing supplies, who popularized the process. This formula is generally referred to as the Na2 method. Sodium chloroplatinate, in contrast to potassium chlorate, does not cause grain. SILVER GELATIN PRINT PLUSThe process using palladium alone ( sodium tetrachloropalladate) is similar to standard processes, but rather than using ferric oxalate plus potassium chlorate as the restrainer (which is ineffective for palladium), a weak solution of sodium chloroplatinate is used instead. Many practitioners have abandoned platinum and only use palladium. A greatly decreased susceptibility to deterioration compared to silver-based prints due to the inherent stability of the process and also because they are commonly printed on 100% rag papers.However, platinotypes that have been waxed or varnished will produce images that appear to have greater D-max than silver prints. Recent studies have attributed this to an optical illusion produced by the gelatin coating on RC and fiber-based papers. The darkest possible tones in the prints are lighter than silver-based prints.Not being coated with gelatin, the prints do not exhibit the tendency to curl.The reflective quality of the print is much more diffuse in nature compared to glossy prints that typically have specular reflections.Some of the desirable characteristics of a platinum print include: It is estimated that a platinum image, properly made, can last thousands of years. The platinum group metals are very stable against chemical reactions that might degrade the print-even more stable than gold. Platinum prints are the most durable of all photographic processes. 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. Unlike the silver print process, platinum lies on the paper surface, while silver lies in a gelatin or albumen emulsion that coats the paper. Platinum tones range from warm black, to reddish brown, to expanded mid-tone grays that are unobtainable in silver prints. Platinum prints, also called platinotypes, are photographic prints made by a monochrome printing process involving platinum. Coming Home from the Marshes, platinum print by Peter Henry Emerson, 1886 ![]()
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