White spots on my Palladium prints

[HiroT]

Hi all,

I’m an amateur photographer working with palladium prints for about three years, most of which was spent gathering necessary equipment and not really being able to explore and improve the process.
Recently, my lab found a workable form and I could finally spend time looking and analyzing my prints. And I realized that there were many tiny white spots on my prints, and they don’t look like they are transferred from my negs or dust. With some prints they are more apparent than with the others, but the used chemicals, paper, and methods are the same from the same batch. I attached the image and I was wondering what may be causing this. Let me know if you knew anything about this!

Some info on my process:
-I use palladium, FO, and Tween20 from B&S on Hahnemuhle Platinum Rag, developed in Potassium Oxalate also from B&S
-I contact print 4x5 negs
-I use a glass rod for 5 drops of Pd and FO with a diluted Tween20 drop for about 4-5 paths (the dilution of Tween isn’t measured exactly which might be one of my problems. I dilute a drop of tween with a drop of water, which is more in quantity than a drop of tween)

 

[nmp]

Usually very difficult to diagnose this kind of problem from a distance. Most folks will consider the paper as the first variable to look at - perhaps use another paper of different make but of similar category (like COT320, HPR, etc.) and see if there is any difference. You might also like to check out this thread where the OP solved a similar (may be not the same) problem of white spots by changing the clearing process. May be something you can try too.

Good luck. And welcome to Photrio.

:Niranjan.

 

[Alan9940]

I would suspect dust, minute bubbles in the coating from the Tween, or, maybe, the water added to the Tween. Did you use distilled water? How old is your FO solution? I don't ever go beyond 6 months.

 

[FotoD]

I'm not a palladium printer, but have seen similar problems in other processes. So this may or may not be of help in your case.

If the white spots look like they could come from particles:
Make sure the pipette draws solution from the top of the bottle. Handle the bottles carefully so that you don't stir up any sediment from the bottom. Only use distilled water to mix your solutions.

If the spots look like white fibers:
Coat the verso of HPR instead. The two sides print similarly, but sometimes the recto looks grainier b/c of white paper fibers. A soft coating brush or more Tween may also help (your use of Tween sounds a bit on the low side).

Good luck!

 

[koraks]

Welcome to Photrio, @HiroT !

The first thought that always comes to me with spots like these, is physical damage to the paper surface during or even after coating. It's more common with brush coating than rod coating, however.

I use a glass rod for 5 drops of Pd and FO with a diluted Tween20 drop for about 4-5 paths

Does this mean you do 4-5 passes over the paper with the coating rod? Try to minimize this number to limit disturbance to the paper surface. A single or only two passes might work better.

 

[jeffreyg]

The paper I use and other papers I have used say to coat a particular side. Check that first. Try using a sable brush. I brush the paper with distilled water first and wait until it is very close to dry before coating. I have found I prefer the brush to a glass rod. I have never run into what you are showing. Could it be static electricity? You could check with Bostick and Sullivan. That’s where I get my supplies and they have always answered questions.

 

[Finn lyle]

I've seen this kind of spotting in kallitype from coating the wrong side of the paper (with Bergger cot 320). Could also be from uneven moisture in the paper- how long was it between coating and printing?

 

[fgorga]

In addition to all of the other good suggestions above, I think that you are using too much Tween 20.

Make a 10% (w/v) stock by weighing 10g of Tween 20 into a graduate cylinder and adding water to 100 mL. Mix well. This stock is stable and can be stored for a long time.

Use 1 drop of this stock combined with your 10 drops of sensitizer.
Consistency in all parts of the process is a key to getting good results in alt process printing.

 

[jprofita]

No one has mentioned the alignment of the planets… I went through the same grain headache with traditional PtPd. Ultimately I switched to Na2 process, brush coated, no Tween, paper hung in my darkroom with a humidifier running until 40-50RH. Fresh ferric Oxalate.

 

[HiroT]

Thank you all for the responses and suggestions! I'll start with checking the side of paper to apply the solution as it would be the easiest to test. Someone else also mentioned to me that HPR is susceptible to the lack of moisture in paper which can often cause these spots. I'll check these two, and work my way out to the suggestions that require purchasing or modifying my process. I'll update my progress once I get around to testing!