Pyrocat oddity

[dpurdy]

I have been using pyrocat for several batches of film in 5x7,8x10 and 120. I am really liking it much better than my previous use of PMK. I haven't seen a streak or any sign of mottling yet and I even improved an underexposed situation with long stand development.. and perfectly smooth tones.

The odd thing I am seeing is a relief on the negatives. I have been using 120 ACROS and going with
water presoak
pyrocat
water stop
kodak rapid fix no hardner
hypo clear
wash
edwals lfn
air dry

the negs I am getting have a relatively extreme relief in the image.. in that the density areas are standing out in three D in the emulsion. Sort of like looking at a really thin printing plate made with gelatin.
It is interesting and even attractive to look at in a skimming light but I am wondering the affect of printing with diffusion or cold light whether the light will wrap around that relief and soften the edges.
I can't say I can notice it just looking at the prints I have made but it seems it has to have some affect.
Is everyone using Pyrocat getting the same thing or is this something I am somehow causing myself?

 

[pgomena]

I haven't seen this effect as strongly with Pyrocat HD and Acros as with PMK and Tri-X. PMK and Tri-X really creates relief. The images print sharp. Someone with more chemical knowledge than I could tell better tell you if this is a result of the tanning/hardening of the gelatin layer or from surface development of the silver halide. Gordon Hutchings talks about it a little in The Book Of Pyro, I think.

Peter Gomena

 

[dpurdy]

Thanks Peter. Do we ever cross paths in Portland?
Dennis Purdy

 

[Kirk Keyes]

Dennis - both you and Pete have almost crossed paths at the monthly meetings we used to have. Pete came a few years ago and you more recently.

Like Pete said, it's an effect of tanning of the gelatin from the pyro developer. Your PMK negs should show some as well. It's believed to help make the negs sharper. It should have no ill effects on your prints.

 

[Rick A]

Its an effect I've noticed with nearly all my films. It shows up on some negatives more than others. I agree with Kirk, and believe that its the reason they print up so well, and the reason it's my number one go to developer these days. I've used D-76 nearly all my years, and finally found a something I like more.

 

[Ian Grant]

It's because Pyrocatechin is a Tanning developer, some films tan better than others, Acros is quite a soft emulsion so it tans more.

Very old glass plates have a very marled relief effect from the stronger Pyro developers that were common pre WWII

Should give you more apparent sharpness in the prints.

Ian

 

[Dan Henderson]

It's because Pyrocatechin is a Tanning developer, some films tan better than others, Acros is quite a soft emulsion so it tans more.

Ian

Slightly off topic, but Ian's comment raises a question for me. I used to develop 120 FP4 and Acros in Dixactol, and noticed that the FP4 took stain much more noticeably than did Acros. Am I correct in assuming that even, as Ian says, that the Acros tans more, that FP4 might take stain better?

 

[Ian Grant]

Possibly, I'll finish some FP4 next week then shoot a roll of Acros. FP4 was once my main film from it's release, but I've rarely used in 24 years, 2 rolls about 12 years ago, and this one's courtesy of Ilford

Different films stain quite different colours in Pyrocat, Acros may well be staining OK but the effect being visually less apparent. HP5 stains noticeably.

Ian

 

[dpurdy]

Thank you for the info. I never knew this affect from Pyro before. I just checked some 8x10 TMY that I processed in Pyrocat recently and can't say that it has that affect though it has a nice stain.

When I was first testing this Pyrocat I did side by side exact comparisons with the same film and same shot processed in Beutlers. I did not notice a sharpness advantage to either over the other. So I guess the relief does not affect sharpness.. though it seems to me it should with cold light enlargement.
The pyro negs in my test had better mid range but the beutlers in my test won the highlight contest.. using VC paper.
Dennis

 

[brucemuir]

slightly OT but this may be beneficial:

I'm using PMK and am wondering if I am gaining the full benefits with a diffusion/tungsten head.

From what I understand the full benefits are realized with a cold light head as the stain filters certain wave lenghts of the cold light head that aren't present in a tungsten light source?

So I guess what I'm asking is will I still get the better highlights Pyro can deliver with a tungsten based enlarger?

 

[Ian Grant]

Bruce the issue is VC or Graded paper rather than which head, diffuser tungsten head is fine, I assume you mean like a colour head. I've printed Pyrocat negs with both with no problems.

Ian

 

[brucemuir]

My understanding (could be flawed) was that since stain was proportionate to silver/density that the stain is what gives the more delicate highlights.

The greenish/yellow pyro stain filters certain wavelengths from the enlarger light source. Since a cold light is fluorescent (?) the light is made up of different wavelengths than a diffusion tungsten source.

Am I on the right track?
I was thinking "if the stain is heavier in the highllghts why dont they block up?" until I read about the filtering effect.

Is this making sense?

edit: ooo..so the VC paper has layers more wavelength sensitive that the graded paper doesn't? I cant write very well what I'm thinking