I have been producing platinum and palladium prints since 2015.
Platinum and palladium prints are 19th century photographic processes that are reportedly the longest-lasting kind of photographic print that can be made, much longer than standard black and white prints that are based on silver. Platinum and palladium are noble metals, and they do not rust or tarnish.
Also known as platinotypes and palladiotypes, the prints themselves are made on natural fiber paper, where the little flecks of precious metal get embedded in the the fibers, leaving a subtly warm tone and a matte texture.
Of the two metals used -- platinum and palladium -- I use palladium because it generates warm tones and I like warm tones. The tonal range of these prints are much richer than that of traditional silver prints -- there are more gradations between black and white and you can often see very subtle detail in the darkest parts of the photograph.
Creating the final print uses a process called "contact printing". The process starts with a digital image that is used to create a printed negative using an inkjet printer, on specialized transparent film. The negative is the same size as the final print.
The image is printed on natural fiber paper that is prepared by hand-applying the platinum or palladium emulsion. Once it dries, the negative is pressed up against the paper inside of a contact frame, and then exposed for up to twelve minutes to ultra-violet light.