Platinum Palladium fogged print?

hiroh · Nov 3, 2024

I’m doing a new calibration after a year, and compared to my previous targets, the new one looks muddy or fogged. What might be causing this?

The developer is a year older than before, but it’s fresh and has never been used. The Ferric Oxalate was mixed from powder two months ago, so that shouldn’t be the issue.

The printing frame is quite tight. I always use several sheets of cardboard under the paper to keep it as flat as possible against the glass during exposure.

Old density target on top, new on the bottom. Notice how much thicker the letters are on the old one.

Any ideas?

Vaughn · Nov 3, 2024

Same batch of paper? That is a big variable.

koraks · Nov 4, 2024

hiroh said:
Notice how much thicker the letters are on the old one.

That's a problem with negative-to-print contact. The light bleeds from transparent areas in the negative and spreads around. That can only happen with imperfect contact.

hiroh · Nov 4, 2024

Vaughn said:
Same batch of paper? That is a big variable.

Same paper, not the same batch.

koraks said:
That's a problem with negative-to-print contact. The light bleeds from transparent areas in the negative and spreads around. That can only happen with imperfect contact.

I suspect that this is the problem, which is why I printed four times. It took me several hours, and the best result I achieved still doesn’t match the quality of the old target. I ended up placing six cardboard sheets under the paper and tightening the printing frame, which is in perfect condition by the way. I used a loupe to examine how the print is making contact with the paper, and everything looks perfect to me. My old targets all turned out well, and I never had to use any additional sheets under the paper before. I simply can’t believe the contact could be better than what I did last night. If I add one more sheet, the glass might break. But, I agree that this seems like a problem with the contact, not the paper or chemistry, but who knows. I'm puzzled.

koraks · Nov 4, 2024

hiroh said:
If I add one more sheet, the glass might break.

Note that glass, especially as surface area increases, can bend/bulge. Adding pressure along the edges can actually make matters worse in the center. This depends on the thickness, surface area and aspect ratio of the glass plate, as well as construction of the contact printing frame.

What kind of frame do you have, what size is it and how does it create contact/pressure?

Also, to rule out the obvious: you do have the printed size of the negative in contact with the printing paper? I.e. 'emulsion to emulsion'.

hiroh said:
I agree that this seems like a problem with the contact, not the paper or chemistry

One doesn't rule out the other, but the problem with the bleed is definitely a problem with contact. Given how uniform it is, I'd start by excluding the obvious mishap of trying to print with the negative upside down. I guess we all fell into that one at some point.

hiroh · Nov 4, 2024

koraks said:
Note that glass, especially as surface area increases, can bend/bulge. Adding pressure along the edges can actually make matters worse in the center. This depends on the thickness, surface area and aspect ratio of the glass plate, as well as construction of the contact printing frame.

What kind of frame do you have, what size is it and how does it create contact/pressure?

I have a three year old Bostick & Sullivan 16x20” printing frame. I’ve never had to use additional sheets, since the frame is quite tight, but (just in case) I’d place one 11x15” sheet under the coated paper, for 11x15” prints. This time, I started with one and then kept adding more 11x15” sheets of cardboard. I may try with 16x20” sheets if nothing else works.

koraks said:
Also, to rule out the obvious: you do have the printed size of the negative in contact with the printing paper? I.e. 'emulsion to emulsion'.

Usually, yes—if I’m printing a real photo, the negative matches the exact size of the paper. This time, however, when printing the target, the negative was slightly larger than the paper strip. The width matched, but the height was about 0.5–1” larger on each side. Hmm, now I’m wondering if this could be the issue. But then again, after several unsuccessful attempts, I checked the contact with a loupe, and it looked perfectly in contact.

And yes—always emulsion to emulsion!

koraks said:
One doesn't rule out the other, but the problem with the bleed is definitely a problem with contact. Given how uniform it is, I'd start by excluding the obvious mishap of trying to print with the negative upside down. I guess we all fell into that one at some point.

I even tried rotating the negative. Among these four attempts, some turned out slightly better than others, but none are as good as they used to be.

I’m almost certain the issue lies with the contact, so I started looking into vacuum frames last night. But i’d be happier to solve the issue with the contact frame as it’s always worked well.

All in all, I’m a bit out of ideas, but I’ll try using larger sheets of cardboard and see how that goes.

koraks · Nov 4, 2024

hiroh said:
the exact size of the paper

My apologies; I made a typo. I meant 'side', not 'size'. Size of the negative doesn't really matter much as long as the printing frame works OK.
The 'emulsion to emulsion' bit was what I was referring to.

16x20" is big. If that's one of the regular spring-loaded, hinge-back frames, I'd expect this may be part of your problem.

The smaller 'pusher' sheets of cardboard padding sound like a bad idea; I'd use sheets that are as large as the glass area. Hope this helps.

For what it's worth, contact problems usually show up pretty irregularly; i.e. it's better in one spot than in another. So the fact that it's pretty even across the strip you've shown is a bit puzzling.

hiroh · Nov 4, 2024

koraks said:
My apologies; I made a typo. I meant 'side', not 'size'. Size of the negative doesn't really matter much as long as the printing frame works OK.
The 'emulsion to emulsion' bit was what I was referring to.

16x20" is big. If that's one of the regular spring-loaded, hinge-back frames, I'd expect this may be part of your problem.

The smaller 'pusher' sheets of cardboard padding sound like a bad idea; I'd use sheets that are as large as the glass area. Hope this helps.

For what it's worth, contact problems usually show up pretty irregularly; i.e. it's better in one spot than in another. So the fact that it's pretty even across the strip you've shown is a bit puzzling.

Yeah, I had an issue before where part of the print turned out blurry due to poor contact, probably from a loose hinge. But this looks different—it’s not blurry, and it’s even. It looks as if I placed the negative upside down, and it bled through the thickness of the transparency.

koraks · Nov 4, 2024

Yes, indeed, that's exactly what it looks like.

Tom Taylor · Nov 4, 2024

"I have a three year old Bostick & Sullivan 16x20” printing frame. I’ve never had to use additional sheets, since the frame is quite tight, but (just in case) I’d place one 11x15” sheet under the coated paper, for 11x15” prints. This time, I started with one and then kept adding more 11x15” sheets of cardboard. I may try with 16x20” sheets if nothing else works."

Keep it flat - use 16x20 for the additional sheets. Using a smaller size introduces a slight bend in the overlaying glass. Also I would suggest that you use a 11x14 frame to print 11x14 paper. The B&S 11x14 frame (12x15 paper) is a lot tighter than the 16x20 frame.

hiroh · Nov 5, 2024

I’m happy to report that a few 16x20 sheets solved the mystery. Now, the letters are as crisp as they used to be.

The problem was that when I started using those 11x15 sheets, it only made things worse. Previously, I wasn’t using anything under the paper, and, obviously, there was no need.

Thanks everyone!

koraks · Nov 5, 2024

Great to hear; happy printing!

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