The Curse of the Black Specs ... a horror film

Hi:

I am new to Pd/Pt printing, and have been having the Devil's own time with step wedges. Now that I have managed to get a Dmax and Dmin (without pooling the negative), I am finding the curse of the black specs on any part of the paper upon which the emulsion was spread. (I am using B&S Ferric Oxalate solution LiPd solution, and NA2 for anti-fogging.) All material except Arches Platine were sourced from B&S. I bought the Arches Platine as large sheets (33 x 40 or some such size) from a local art supply store. Come to think of it they gave me a discount because of a few indents, and complained that the new stockroom boys were not as careful as they should be. The obvious culprit is the paper, (and I will see if I can buy some boxed and pre-cut sheets for testing just to verify that it is or is not metal spec contamination.) I cut some strips for wedges using metal scissors. I may have to find a non-metalic ruler to rip a strip from the other side of the sheet to verify that the scissors are not the problem.

If anyone has thoughts about another source of the problem please reply. (I may have to throw out about 10 large sheets if it is the paper .... Argh!)

Just a quick question...are you using a sheet of mylar or something similar between the negative and the paper?

The black specs you're seeing might not be contamination, but might be transfer from the negative to the paper. Check to see if there's ink missing in the corresponding spots on the negative. You may need to give the negative longer to dry before printing.

On pictorico, the back of the negative looks cloudy in areas of heavy ink. That goes away once it's dried completely.

Of course, it could be contamination, but I know others have run into problems of ink transfer.

Good luck--

Greg

Thanks Greg,

I have been maxing out the substrate with ink to get my Dmin, so that is definitely a possibility. I will reprint next weekend using the step wedge I created today.

Is there a rule of thumb abound drying time with negatives, and is it best to just let them rack or hang-dry?

Much appreciated,

Nick.

- You can use a hair dryer to blow dry your digital negatives. 45-60 seconds works for me.
- I *always* put my negatives in 2 mil polypropylene bags -- easy to print, easy to store
- if you still see specks after drying your negatives, then I would suspect the chemistry. I doubt the
paper itself is the culprit. I guess it's possible, but I cut all my papers, including Platine, with scissors and paper
cutters with metal blades and I have never seen specks. Try filtering your oxalate and palladium through fine
cotton and rebottle.
- I don't think Platine is manufactured in sheets smaller than 22x30. If you find smaller sizes the vendor must be
cutting up larger sheets.

Zero_Equals_Infinity said:

Hi:

I am new to Pd/Pt printing, and have been having the Devil's own time with step wedges. Now that I have managed to get a Dmax and Dmin (without pooling the negative), I am finding the curse of the black specs on any part of the paper upon which the emulsion was spread. (I am using B&S Ferric Oxalate solution LiPd solution, and NA2 for anti-fogging.) All material except Arches Platine were sourced from B&S. I bought the Arches Platine as large sheets (33 x 40 or some such size) from a local art supply store. Come to think of it they gave me a discount because of a few indents, and complained that the new stockroom boys were not as careful as they should be. The obvious culprit is the paper, (and I will see if I can buy some boxed and pre-cut sheets for testing just to verify that it is or is not metal spec contamination.) I cut some strips for wedges using metal scissors. I may have to find a non-metalic ruler to rip a strip from the other side of the sheet to verify that the scissors are not the problem.

If anyone has thoughts about another source of the problem please reply. (I may have to throw out about 10 large sheets if it is the paper .... Argh!)

Click to expand...

Zero_Equals_Infinity said:

Is there a rule of thumb abound drying time with negatives, and is it best to just let them rack or hang-dry?

Click to expand...

Like I said, I wait until there's no cloudiness when looking through the back side. This is usually 1-2 hours depending on temperature and humidity. Or, I use an hot-air RC print dryer (with the racks, not the rollers), and that just takes a couple of minutes.

--Greg

Ok- first, clarify what chemical process are you using - are you doing PoP (Printing-out Process) palladium prints using the LiPd? Or are you trying to do develop-out palladium and processing in Potassium Oxalate? NA2 is a contrast agent and while I'd call Bostick & Sullivan to verify this, I don't know that it works (or works well) with the LiPd process. There are several other contrast agents you can use with LiPd, namely Sodium Tungstate (contrast reducer, lends a warm to reddish tone), Gold Chloride (contrast booster, goes anywhere from cool neutral to purple, depending on quantity), Ammonium Dichromate (contrast booster) - those are the three I can think of off the top of my head, but there may be others as well.

Regardless of contrast agent, it sounds like you're getting "the black plague" - Platine was notorious for this. It's a chemical reaction between something in the paper and the palladium (or platinum) chemistry. You can TRY giving the paper an acid pre-bath to see if it helps, but it probably won't fix it. I would try switching your paper - other highly recommended papers are Fabriano Artistico, Rives BFK, Bergger COT320 (my personal favorite). Do some research on APUG, our sister site, as to papers for pt/pd, and also look on unblinking eye (Unblinking Eye - photography, darkroom, alternative process, historic photographic processes, travel) and alternativephotography.com (AlternativePhotography.com). When all else fails, call Bostick & Sullivan - they always take the time to talk to you about whatever your questions or issues might be.