The term “Platinum Print” in general usage encompasses the use of both platinum and palladium in ratios of 100:0 to 0:100 and everything in between. Most “platinum prints” are in fact platinum/palladium prints. It is possible, but very difficult, to produce a pure platinum print of high quality.
Tint (or image color) is controlled to a degree by varying the ratio of platinum to palladium. More platinum resulting is a more neutral (charcoal-like) tint, more palladium resulting in a warmer (browner) tint. However, there are other variables that have as much if not greater effect. The major ones are:
- The paper. Some papers print are inherently warmer or more neutral than others. I don’t mean simply the tint of the paper itself. In fact, all other variables being constant, an image will usually appear warmer on a whiter paper base than it does on a warmer paper base. This is similar to the effect of putting the same piece in a black frame vs a brown frame.
- Choice of Developer. There are several possible developers for Pt/Pd printing. The most commonly used, and the 2 that I have experience with, are Ammonium Citrate and Potassium Oxalate. Citrate produces a more neutral image; oxalate warmer.
- Temperature of the developer. Warmer developer temperature results in warmer image tone.
In my own work I usually strive for maximum warmth. 100% palladium on Arches Platine developed potassium oxalate developer heated to 120-140 degrees F.
To achieve a neutral image tone I might choose a different paper (not sure), use a 50:50 blend of platinum and palladium (maybe even a bit more platinum), and develop in ammonium citrate at room temperature.
It is fairly easy to learn to make decent Pt/Pd prints. But the process is rich in possibilities and you can delve into it much deeper if your interest takes you there. My journey into Pt/Pd began almost 25 years ago and I am still learning. I still work with original large-format film negatives mostly, though I have made digital negatives occasionally since the late ’90s. The use of well-made digital negatives has the substantial benefit of standardizing many of the variables involved in contrast control. In other words, digital negatives can and should be tailored to eliminate many of the variables of the process that are concerned with controlling contrast.
I feel that the most difficult part of the Pt/Pd process is learning to coat the paper. Because platinum and palladium are so expensive, it would be well worth your while to practice coating with an inexpensive process such as cyanotype.
(Adapted from a post that I contributed to a question on the Digital Black and White group on LinkedIn.)