Platinum printing question.

[Noel Peirce]

I have recently completed a few platinum-palladium prints using the Bostick & Sullivan kit. I was reasonably satisfied with the results, just need to fine tune the contrast technique. What I am concerned about is an overall very light tinge of yellow in the white areas of the print. Even with rewashing this sort of yellowish stain remains. Anyone have some ideas or suggestions as to what I may have done wrong or how I could solve the problem. The printing paper was 100% rag cotton made by Bergger.

[ndg]

I have recently completed a few platinum-palladium prints using the Bostick & Sullivan kit. I was reasonably satisfied with the results, just need to fine tune the contrast technique. What I am concerned about is an overall very light tinge of yellow in the white areas of the print. Even with rewashing this sort of yellowish stain remains. Anyone have some ideas or suggestions as to what I may have done wrong or how I could solve the problem. The printing paper was 100% rag cotton made by Bergger.

If the water you are using to clear the print after you take it out of the developer is alkaline, you may stain the print. You could acidify the water with citric acid - 30 gm/liter or even white vinegar. I've done 30 cc/liter.
What do you use to wash the print? There are several recipes and methods out there. I use 2 baths. Each has 2 liters of water with 1 tbsp of EDTA and 1.5 oz of Permawash. I leave the print in each bath for 5 min. Works really well. I use Arches Platine paper but I don't think it makes a difference.

[keith schreiber]

That yellow stain is residual sensitizer (ferric oxalate) that has not been removed by the clearing bath(s). No amount of washing will remove it. What are you using to clear your prints and what procedure are you using? If you are using EDTA alone, that is probably your problem. It seems to work ok for a few pt/pd printers, but most of us have found it to be insufficient with most papers. The water chemistry in your particular location may be a contributing factor.

If you have citric acid on hand, try adding some of that to your EDTA clearing bath - about 1 tablespoon per quart (or liter).

If you have Kodak Hypo Clear on hand, try clearing in 3 successive baths of that at standard working strength - 5 minutes in each bath. The first bath will turn yellow/orange fairly quickly. After a couple of prints when you start to see signs of yellow/orange in the second clearing bath it is time to dump the first, move the second to the first position and the third to the second, and make a fresh 3rd clearing bath. The third should always be completely clear.

The clearing bath formula that I settled on after much experience, and have been using for about 2 decades now is as follows:

• water at room temp - 1 liter
• EDTA (tetrasodium) - 1 tablespoon
• citric acid - 1 tablespoon
• sodium sulfite - 1 tablespoon

Add the ingredients in the order listed and be sure each is dissolved before adding the next. Always use a sequence of 3 baths and rotate them as described above. Five minutes in each is typical for most papers, but some may need more time and some less.

Other printers will probably suggest other clearing procedures but they are all variations on this theme.

Good luck,
Keith

[angusparker]

A recent class I took suggested the following three clearing bath process with five minutes in each: Bath 1) 2 tbsp citric acid in 1l. Bath 2) 2 tbsp citric acid in 1l. Bath 3) 1 tbsp of EDTA in 1l. I find that these baths work for only a while, say 4-5 8x10 prints, before the start to yellow and need to be replenished - at least the first one. The process described above seems very robust and I might change the way I do it!

[gubaguba]

I tried to only use distilled water when palladium printing extreme maybe but it eliminated any guessing I may have had when problems happened. Super important to stay consistent with the processing as there would always be slight variables in coating the paper. That said yellow tinge would suggest ferric oxalate has not been completely washed out.

You might want to run some test: run a small piece without exposing to make sure nothing is contaminating your paper. If that clears then your processing is okay.

I found that heat from exposure could cause problems sometimes as well.

Remember to have fun.

[Noel Peirce]

My thanks to all of you who have submitted suggestions. I feel confident that I can correct this problem now that I have a little more knowledge of the situation. Again my thanks to all. (Noel)

[angusparker]

I tried to only use distilled water when palladium printing extreme maybe but it eliminated any guessing I may have had when problems happened. Super important to stay consistent with the processing as there would always be slight variables in coating the paper. That said yellow tinge would suggest ferric oxalate has not been completely washed out.

You might want to run some test: run a small piece without exposing to make sure nothing is contaminating your paper. If that clears then your processing is okay.

I found that heat from exposure could cause problems sometimes as well.

Remember to have fun.

I should have added I use distilled water in all clearing baths (and developer). Only tap water for final rinse for at least 10 minutes continuous flow.

[Cletus]

I had the same problem with the yellow stain starting out. As others have already said, it is almost definitely residual iron from the sensitizer. My clearing baths (two of them) are the same and consist of 2tbsp Sodium Sulfite + 1tbsp EDTA to 1L tap water, dissolved one at a time with a magnetic stirrer (or just a stick). I use this clearing bath the same way for all papers: Arches Platine, Kozo, COT320, Rives and a few others, mostly Arches - results appear about the same all around. Some say Citric Acid or EDTA, but I don't see why both together wouldn't work just fine. I've always used pure Sodium Sulfite, but it's probably the same difference using Perma Wash, or other Hypo clear type mixture.

I have a Bath #1 and Bath #2, five minutes in each with a quick rinse between, followed by a final wash of 30 mins to an hour in a standard print washer. When Bath #1 starts getting...dirty, Bath #2 becomes Bath #1 and make a new batch for #2. I usually get about 4-8 8x10 prints and a few test strips before a fresh #1 bath is needed. My tap water quality is pretty good, YMMV. If you have a lot of calcium in your water, I would think that might impede the process somewhat.

[keith schreiber]

Kodak Hypo Clearing Agent (powder) consists of

• sodium sulfite (75-80%)
• sodium metabisulfite (15-20%)
• sodium citrate (1-5%)
• EDTA tetrasodium (1-5%)

It provides the necessary components of an effective clearing bath for Pt/Pd prints. The use of KHCA was first suggested to me nearly 2 decades ago by Kerik Kouklis when I was having a similar issue as that described by the OP but with Arches Platine. It worked. Until that time I had been using phosphoric acid for clearing.

Perma Wash may work (I have not used it) but it contains ammonium sulfite and other ingredients that are a trade secret according to the MSDS.

The purpose of the citric acid in the formula I gave previously is to convert the tetrasodium EDTA to the more reactive disodium form. (Reference alt-photo-process list, message from Howard Efner 1/6/2003.)

Also, I strongly recommend using a 3 bath clearing sequence rather than 2. This will assure a fresh final clearing bath. The first bath does the heavy lifting, the 2nd probably gets you 95% cleared, and the 3rd insures that the process is complete. By the time you notice some color in the 2nd bath, it is too late for it to be a good final bath. Think of the 3rd bath as cheap insurance.

~ Keith

[Doug Howk]

Not an expert, but my limited knowledge and experience with pt/pd does suggest that some of the yellowing may be due to the developer. I switched to Potassium Oxalate and have not noticed the yellow stains. Just a thought.