Hi all,
I have a problem with, what I believe is, calcium oxalate forming on my palladium prints. There is a good topic on this, but it appeared that CO wasnt the culprit in the end and the discussion ended there.
The details: (I have always used ammonium citrate until now, and have had no problems with the workflow.) I develop the prints in PO (mixed with tap water) at room temp. I then move the print straight to a clearing bath of tri-sod EDTA and sodium sulphite (again mixed with tap water). A plain water bath has produced clearing issues in the past. Within a couple of minutes, minute, insoluble crystals/scum form all over the print, which rub of as a yellowish powder when dry.
A couple of observations:
Ideally, I should just ditch everything and start again with distilled water, but since PO is about 25 GBP per litre, I would like to avoid this. Does anyone know that if I mix the clearing bath with distilled water, will there be insufficient calcium from the PO to form the crystals? Or, that although the problem appears to form in the clearing bath, it does in fact happen in the PO but manifests itself in the clearing bath. The fact that the first print is OK suggests to me that, for some reason, the (increasing amount of) oxalate and calcium in the clearing bath is responsible. Any suggestions? I don't really want to ditch the equivilent of $100 of PO.
Also, perhaps a different thread, but perhaps related, I find the PO a little too warm. I have heard it possible to combine Po and ammonium citrate to produce a slightly cooler developer. Is this correct? And, as an aside, would the reduced oxalate in the dev, reduce the probability of creating CO on the print?
Or is it something completely other than CO???? My FO is getting on the old side, but I don't se how this would create these problems.
So many questions.
Many thanks
Geoff
I have a problem with, what I believe is, calcium oxalate forming on my palladium prints. There is a good topic on this, but it appeared that CO wasnt the culprit in the end and the discussion ended there.
The details: (I have always used ammonium citrate until now, and have had no problems with the workflow.) I develop the prints in PO (mixed with tap water) at room temp. I then move the print straight to a clearing bath of tri-sod EDTA and sodium sulphite (again mixed with tap water). A plain water bath has produced clearing issues in the past. Within a couple of minutes, minute, insoluble crystals/scum form all over the print, which rub of as a yellowish powder when dry.
A couple of observations:
- The first print is fine, the second, the crystals are visible only when the print is dry. The third print is covered. This suggests to me that as the clearing bath gets loaded (which is quickly since I use no water bath and PO does not clear as effectively as AC), the problems occur.
- The crystals only form on the area of the paper that has been coated. Borders are free.
- Double-coated prints are much worse.
Ideally, I should just ditch everything and start again with distilled water, but since PO is about 25 GBP per litre, I would like to avoid this. Does anyone know that if I mix the clearing bath with distilled water, will there be insufficient calcium from the PO to form the crystals? Or, that although the problem appears to form in the clearing bath, it does in fact happen in the PO but manifests itself in the clearing bath. The fact that the first print is OK suggests to me that, for some reason, the (increasing amount of) oxalate and calcium in the clearing bath is responsible. Any suggestions? I don't really want to ditch the equivilent of $100 of PO.
Also, perhaps a different thread, but perhaps related, I find the PO a little too warm. I have heard it possible to combine Po and ammonium citrate to produce a slightly cooler developer. Is this correct? And, as an aside, would the reduced oxalate in the dev, reduce the probability of creating CO on the print?
Or is it something completely other than CO???? My FO is getting on the old side, but I don't se how this would create these problems.
So many questions.
Many thanks
Geoff