First, it is not the platinum family of metals that form the image under ultraviolet light. The light sensitive metal is ferric oxalate, which reacts on exposure to UV light to give ferrous oxalate. The ferrous oxalate which is formed by the UV light functions as a reducing agent which converts the noble metal salt to a metallic state via a chemical reaction.
I don’t see a contradiction with this Sandy. You’ve described how the image forms at a deeper level of detail than I did. For the lay public it’s enough to say that image is formed from the noble metal. For people who want to know more, there’s a chemical process involved as you’ve described.
Second, many people (those who use only palladium salt in the emulsion and dichromate as the contrast control) print only in pure palladium and don't use any platinum metal at all. Is it OK to call these platinum prints even though they contain zero amount of platinum?
I was trying to find a form of words that meant that using platinum is a requirement to it being called a platinum print, while other metals are an additive. Personally I wouldn’t consider a “pure” palladium print to be a platinum print with or without trace amounts of platinum. I think it would also be stretching things to call an extreme Pt
d ratio such as 1:11 a “platinum print” but I’d rather leave it to people’s conscience than try to dictate a purity standard.
Perhaps this would be a better first sentence: “A platinum print is a print made using one of several processes which uses platinum to form an image under ultraviolet light.”
Also, I frequently make kallitype prints which are then toned with either palladium or platinum. Since the more noble metal replaces the silver metal the final print is one which is made up of a very high percentage (90% plus) of the toning metal. In essence, if I tone a kallitype print with platinum the print then contains a much higher percentage of platinum metal than a print made from pure palladium (which contains no platinum at all), or for that matter the toned kallitype contains more platinum metal than a print made from a 1:1 mix of palladium and platinum salts in the emulsion. Is it OK to call these platinum toned kallitypes platinum prints?
My instinctive answer is that “platinum toned kallitypes” is a more appropriate label. I’m no expert on kallitypes (so would bow to your and others judgement), but if there’s a fundamentally different process then to label them “platinum prints” would seem like an attempt to deceive.
As I said earlier in the thread, there should never be an attempt to deceive. The important thing is that our communication is pitched at the right level for the audience. That means balancing the need for full disclosure with the need to be understood – and it’s more important to be understood than it is to reveal all the technical details.
I think the real point is that many people want to use the term "platinum printing" because the word platinum is pretty much a synonym for something that costs a lot, and that is the real appeal of these prints to the "lay public." By contrast, the lay public by and large knows nothing about palladium, and even though pure palladium is in many ways a much more elegant process than pure platinum, or pt/pd, it does not speak money as does platinum.
It’s the nature of our society that the rarity (and price) of raw materials is a significant influence on the market price charged for an artwork. People tend to pay more for a gold necklace than they do for a silver necklace, but in many ways silver is a more beautiful metal than gold. Similarly, in the past painters often used ultramarine (lapis lazuli) specifically because by doing so they demonstrated the wealth of their clients.
Perhaps some people do feel the need to label their palladium prints as “platinum prints” for this reason, although I haven’t seen this personally. This would sadden me because, although I don’t particularly like the palladium aesthetic (that’s just my taste not a value judgement), I would hope that people would call a palladium print a “palladium print” and allow the strength of their work to create the value.