CHRYSOTYPE -THE GOLD PROCESS
Traditional monochrome photographs are based on silver. However, in the earliest days of the art, photographers explored the use of a variety of other metals in processes referred to collectively as “alternative” or “non-silver” photography. Chrysotype is unique among them, in that it is based on GOLD.
The process was discovered by one of the earliest figures in photography, Sir John Herschel, but it was so difficult and problematic that it was little used for many years. Over 150 years later, Dr Mike Ware, a British chemist with a long-standing interest in alternative process photography, spent a decade in refining and modifying the process so that it can be used more confidently today. The technique is still lengthy and complex, but with practice consistent results can be obtained, though each image remains individual and unique. (It goes without saying that it is also comparatively expensive, but fortunately the quantity of gold solution required is very small, applied in small drops with a syringe or pipette before being very thinly spread with a glass rod.)
As with many other alternative photography processes, chrysotype begins with choosing and coating a sheet of watercolour paper. Three chemical solutions are mixed together immediately before use: one provides the sensitivity to light, one (with the gold) provides the colour range, and the third binds the molecules of the first two together.
Water is a key element in the process. In the first, paper preparation, stage, you want to get rid of it, and some time is spent drying the coated paper with a hair dryer. Later, in the development process, the right balance of air humidity and steam is required to achieve the best result.
Like many other non-silver processes, chrysotype involves contact printing; that is, the negative is placed in direct contact with the treated paper before exposing it to ultra violet light. Consequently, the final image can only be as big as the negative from which it is obtained. After exposure, the print is steamed and developed, after which it goes through a succession of water and chemical baths. If you get the balance of dryness of paper, steam, humidity in the room, type of developer and length of exposure correct, you are rewarded with beautiful ‘split tones’, from pinkish brown mid-tones to slatey blue highlights.