The Platinum Palladium Print
Platinum palladium printing is a traditional photographic printmaking technique dating back to a period in photographic history that predates silver gelatin prints. The prints are exposed by UV light, and were originally exposed by the sun. The prints are created by way of "contact printing" which means the photographic negative must be as large as the final print. This limited fine art photographers until the digital age, where we can now create what are known as "digital negatives." These negatives can be printed at nearly any size and can be used to create platinum palladium prints up to 40" wide.
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 platinum 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. The mixture of platinum and palladium can create a balance between the two appearances and tonalities, which is applicable to some images. Platinum and palladium prints are the most durable of all photographic processes. The platinum (and sister element palladium) element is incredibly stable against chemical reactions that may degrade the print, and is even more stable than gold.
Paper is coated with a platinum/palladium mixture, combined with hydrogen peroxide and ferric oxalate. The mixture is brushed onto the paper slightly larger than the negative, which can be seen as brush strokes in the final print. This coating is what makes the paper light sensitive to ultraviolet light.
After the paper has dried, the negative is placed over the paper and exposed to UV light. During this process, the print can be dodged and burned to affect the tonalities in the final image. After the exposure, a "latent image" can be seen on the print.
Following the exposure, the print is developed in a variety of different developers, depending on the concentration of platinum and palladium. The development is nearly instantaneous. As soon as the developer is poured onto the paper, the final print comes alive. The print is then cleared and washed for 45 minutes.