Lithium vs. Sodium Chloropalladite

[Barry S]

I've just started to get into palladium/platinum printing and I'm wondering if there's any good reason to use the sodium salt of palladium over the lithium salt. From what I've read both salts are fairly comparable. I'd also like to try some printing out palladiotypes (aka ziatypes), and that process uses the lithium salt. It seems there's no reason to use the sodium salt if I have any intention of doing ziatypes, but if that's the case, why does Bostick and Sullivan recommend the sodium salt for the developing out process and the lithium salt for the printing out process?

 

[deisenlord]

I use lithium exclusively for DOP palladium as I like it's warmth, it's also slightly hygroscopic which should help keep moisture in your paper.
No reason not to use it for DOP, especially if you want to mess with POP.

 

[Barry S]

Thanks--so would you say it's slightly warmer than the sodium salt?

 

[Barry S]

Update: I've done my own initial comparison of lithium vs. sodium chloropalladite and I got some interesting results. I compared Bostick and Sullivan sodium chloropalladite solution (palladium solution #3) vs. lithium chloropalladite solution I mixed myself (2.3g palladium chloride, 1.76 lithium chloride, 25ml H2O, [per R. Sullivan]). The sodium chloropalladite solution is several years old. I printed using a 4x5" negative shot on Arista EDU 200 (Fomapan 200) and developed in Pyrocat HD (rotary processing, 1:1:100), that had been developed for normal silver gelatin printing.

Results
Achieving equivalent prints on Weston Diploma Parchment required an exposure of 11 minutes and 1 drop of 20% NA2 with sodium chloropalladite, compared to an exposure of 3 minutes 45 seconds and 1 drop of 5% NA2 with lithium chloropalladite. In other words, the lithium chloropalladite coating was significantly faster and more contrasty. I didn't observe any difference in the warmth of the prints (developed in room temperature potassium oxalate).

Two possibilities come to mind. Either the sodium and lithium salts perform differently in terms of speed and contrast (at least on the Weston paper) or the sodium chloropalladite solution has degraded with age--losing speed and contrast. The obvious follow-up experiment would be making my own sodium chloropalladite solution, but I'm not anxious to do that given my preference for the speed and more economical NA2 use of the lithium chloropalladite. Has anyone seen similar results?