Platinum /Palladium ratio -> Print tone?

I'm gathering all the supplies needed to start doing some Pt/Pd printing. I've been reading all the info online and watching the videos out there. Picked up the Christopher James book and the Ian Leake book is on the way. But, what I haven't yet encountered is some sort of discussion/rough guide to the PT/PD drop ratio to print tone.

If the the range is from warm brown (all Pd) to cool silvery (all Pt.) if would be great to have some sort of rough visual or descriptive guide as how much the ratio of drops of each in the sensitizer effects the tone of the print. Knowing that developer choice and temp have a great influence of final print tone. (I'm intending to print with room temp developer using ammonium citrate developer.)

In terms of silver printing I like Ilford Warm Tone fiber paper. I'm aiming for something similar or slightly warmer in tone.

It doesn't take much platinum in the mix to significantly cool down a palladium print. Even adding a drop or two of NA2 contrast agent to a palladium print will knock the warm off. I don't know that anyone has done a comprehensive study of ratios, but from informal observation, it's not a linear relationship. A 50/50 blend will not be halfway beween the cool of pure platinum and the warm of pure palladium. The tipping point is probably somewhere around 25-30%, beond which it doesn't really change the look any further. From a budget standpoint this is great news, as palladium is a lot cheaper than platinum.

Using ammonium citrate developer with palladium will create a more neutral tone than with potassium oxalate developer. In my printing practice, I strive to create prints with pure palladium, as it has the longer scale, and it is beautiful with the oxalate developer for warm creamy tones. The platinum is used as a contrast agent, either the potassium or sodium (sodium creating a much higher contrast than the potassium).

Everyone has their own personal mixture and favorite paper to coat. I understand that one persons mix might give slightly different looks for someone else. For most of my negatives (depending on size) I use 8 drops pd, 3 drops pt (potassium), 2 drops au (5%), 1 drop chlorate, 12 drops ferric oxalate sol 1(Bostick & Sullivan) and 4 drops distilled water. If I need more contrast I substitute h202 for the water if less contrast omit the chlorate and add a drop of ferric oxalate. I develop with ammonium citrate. I get nice rich warm tones and prefer a natural shade paper. I recently made some prints on vellum backed with 24 carat gold and some backed with sterling silver inspired by Dan Burkholder.

http://www.jeffreyglasser.com/

Not to mention all the different colours of paper we print on.

In terms of paper, I'm going to start with the Arches Platine and Bergger COT 320.

karl said:

I like Ilford Warm Tone fiber paper. I'm aiming for something similar or slightly warmer in tone.

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It's quite difficult to give a meaningful description of tones because they are affected by lots of factors. I would start with a pure Pd sensitiser. If you like that then you don't have to spend money on Pt. But if that's too warm for you then try a 2:1 Pdt mix. That will be quite a lot cooler, but still warm.