on platinum was quite weak, but that perhaps something could be combined with platinum to increase its sensitivity. Through experimentation, he eventually found that ferric oxalate was a highly-effective enhancer. The combination of these two metals remains the basis of the platinotype process in use today. In 1832, Englishmen Sir 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 and albumen 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. Patents William Willis was the first to patent the platinotype process in 1873 (British Patent No. 2011, June 8, 1873), and again in 1878 and 1880, which he leveraged to gain commercial success in the manufacture of platinum papers sold through his Platinotype Company for professional and amateur use. He also developed the palladium process requiring palladiotype paper and a silver-platinum paper, Satista. 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. Commercialization While Willis had greatly advanced the chemistry of the platinum process, there was still no reliable method for