Cooling Down Pt/Pd Tones, Sullivan's Cold Bath Developer Anyone?

[....Jeff....]

Hi Everyone,

I've begun doing some testing using Pt & Pd in 1:2 and 1:1 ratios and am just not getting as cool tones as I had anticipated when developing with (virgin) potassium oxalate at room temp. I know that switching to ammonium citrate will cool things down significantly, but I tend to prefer the appearance of prints developed in the oxalate. I was wondering if anyone has any experience using Sullivan's Cold Bath Developer. According to the formula provided by both Arentz and James, the main constituent is potassium oxalate, though it's at a lower concentration than in a straight PO developer (150gm/L vs 330gm/L). There is also 75mg of potassium monobasic phosphate per liter.

For those of you who are more chemically inclined than most, how crucial do you think the 75mg of PMP is in this formula? Can cooler tones be achieved by simply using a lower concentration of PO and developing for longer? Just curious, as the weight differences in the solutions vary noticeably. I don't have any crystalline PO on hand right now, but may try a dilute solution next time out of curiosity, I can always bring it up to a saturated solution if it doesn't work out. Has anyone tried this?

I know, Iknow, I could print pure platinum, but my wallet is already puckering from using a 50% mix, so I would prefer to explore other alternatives. Any suggestions appreciated.

Thanks,
Jeff

 

[Loris Medici]

Not a direct answer to your question but; if your main goal is to have neutral or cool toned prints, then I would strongly suggest that you also investigate pop pd process option... (= ammonium iron(III) oxalate sensitizer + lithium tetrachloropalladate or ammonium tetrachloropalladate metal solution - no platinum at all!)

Regards,
Loris.

 

[clay]

I use cold bath during workshops so I don't have students slopping around hot potassium oxalate. But the deal is, it produces print tones at room temperature that are about as warm as my straight potassium oxalate developer at 110 degrees. In fact, if you want a really warm print, heat the cold bath developer- Talk about warm toned! The downside to this developer is that it seems to get dirty faster.

The Bostick and Sullivan notes on this developer assert that this developer will deliver cold tones when it is chilled to 50 degrees or so. I have not tried this, so I cannot say one way or the other.

If you want the coldest, blackest tones, use a 50/50 pt/pd split, fresh potox at room temperature and then use the gold-toning recipe from the Bostick and Sullivan site. It produces a nice purply black tone and an increase in print dMax. It is a bit tricky to use, but is very effective. You do need a signficant amount of pt salt in the coating mix, though. If you use straight pd in the coating solution, the gold toning will produce a wild magenta/mahogany tone.

 

[....Jeff....]

Loris,

I have thought about taking a run at ziatypes and may eventually do so. Could you (or anyone else with such experience) tell me how the Dmax obtained in ziatypes compares to that of Pd and Pt/Pd prints.

Clay,

Thanks for the info. I was under the impression that the cold tone developer (at normal temps) had the exact opposite effect of what your experience is. "Several developing agents are available, ... or Sullivan's cold tone developer (cooler tones)." (Arentz 31, 2 ed.) This is why it pays to ask questions and pick the minds of others for information. I am curious to see what this developer, or maybe even stock PO, is capable of chilled. I had never really considered chilling developer, but suppose that it stands to reason that the cooler the developer, the cooler the tones. I will probably explore that a little. Food for thought.

Thanks again guys,
Jeff

 

[pschwart]

I can get a dmax up to log 1.6 in ziatypes; log 1.4-1.45 is pretty typical.

Could you (or anyone else with such experience) tell me how the Dmax obtained in ziatypes compares to that of Pd and Pt/Pd prints.

 

[Loris Medici]

Yes, log ~ 1.5 is pretty achievable in my experience...

 

[....Jeff....]

Sounds good. Thanks, I'll keep the process in mind as a viable alternative.

 

[sharperstill]

I've been using Sodium Citrate as a developer for my latest project. I too are interested in cooler/neutral tones but have found that Sodium Citrate at 25-30C gives me quite neutral tones that are smoother than the cold formulation from Sullivan. Bear in mind also that my prints are either 80%Pd to Pt (usually) or made with NA2 as the platinum component.
I purchased mine (in Australia) from a veterinary supplier (they use it on horses!) quite cheaply and simply made a saturated solution (approx 200-250gms/litre). If you can find some I'd recommend you try it and see if you like it.

Jon