Palladium printing (or platinum palladium printing, depending on the used metals) is a traditional photographic printmaking technique, which dates back to a period that predates silver gelatin prints. The prints are contact prints (the negative is the size of the print) exposed by UV light. Platinum palladium prints are unparalleled by any modern printing technique, both in appearance and performance. These prints are favored by art collectors due to their longevity and appearance. The tonal range of palladium prints are unmatched, even by modern digital inkjet printers. The final color tonality can range from warm black, to reddish brown, with a range of grays in the midtones. Pure platinum (platinotype) prints tend to have a higher contrast and cooler tones, while pure palladium (palladiotype) prints can tend to have warmer appearance with deeper blacks and softer highlights.  Palladium prints are the most durable of all photographic processes. The palladium element is incredibly stable against chemical reactions that may degrade the print, and is even more stable than gold. These prints are less susceptible 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. I use Hahnemühle platinum rag or Bergger Cot.