Mottled skies

[bgh]

I'm getting some odd mottling in the skies of several of my 4x5 negatives this year. I'm a bit flummoxed, as I can't seem to figure out why. I've attached a few scans from negatives over the past couple of months, all with different lenses, and no filters. There was a problem with controlling the water temperature in the darkroom, which I thought might be the source, but I've been keeping a much tighter control on the temperature, and I still get some funky skies. I'm processing with hangers in tanks, with the same agitation regimen that I've been using for years. The only thing that I can think of is that I've starting using Ilford FP4 and HP5 lately, after years of TMY, but I can't figure out what that would have this kind of effect.

Has anyone here had any experience with these kind of mottled skies? Any advice would be gratefully received.

With thanks in advance,
Bruce

177524177526177525

[mpirie]

Bruce, It might help if you pass on the dev, dilution, pre-wash details etc.

Certainly looks like uneven development to me.

Mike

[Doremus Scudder]

If this is uneven development in the skies and not some mist/clouds that you overlooked at the time of exposure, then it really has to be an agitation issue. I don't work with hangers and tanks, so I can't give any specific advice there, but generally, make sure agitation is adequate at the beginning of the development and regular thereafter. Photo number 2 just looks like clouds to me, though...

Best,

Doremus

[bgh]

Bruce, It might help if you pass on the dev, dilution, pre-wash details etc.

Certainly looks like uneven development to me.

Mike

Thanks, Mike. I'm using Sprint chemistry, freshly mixed to the manufacturer's specifications. The negatives get a presoak of nearly two minutes (10 Hail Marys, to be precise...), then into the developer. Once in the soup, I agitate continuously for about 45 seconds (both up and down and forward and back), and then for 5 seconds every 30 seconds for the rest of the time. From there, one minute in the stop both with continuous agitation, then three minutes in the rapid fixer.

Thanks again,
Bruce

[bgh]

If this is uneven development in the skies and not some mist/clouds that you overlooked at the time of exposure, then it really has to be an agitation issue. I don't work with hangers and tanks, so I can't give any specific advice there, but generally, make sure agitation is adequate at the beginning of the development and regular thereafter. Photo number 2 just looks like clouds to me, though...

Best,

Doremus


Hi Doremus--

I agree with you and Mike, this does look like uneven development. I'm flummoxed by why, as I am using the same procedure that I've used for years, but only recently am I seeing skies like this. I will pay more attention to each step, and figure out if I've changed things.

Thanks,
Bruce

[mpirie]

I wonder if the two minute pre-soak isn't long enough for a traditional emulsion like FP4, compared to TMY?

I had to increase my pre-soak for FP4 to 5 minutes (25 Hail Mary's) from 2 minutes when i started with Pyro.

If the only variable you've changed is the filmstock, then it may be that FP4 needs to be handled differently from TMY?

Mike

[mmerig]

I wonder if the two minute pre-soak isn't long enough for a traditional emulsion like FP4, compared to TMY?

I had to increase my pre-soak for FP4 to 5 minutes (25 Hail Mary's) from 2 minutes when i started with Pyro.

If the only variable you've changed is the filmstock, then it may be that FP4 needs to be handled differently from TMY?

Mike

Ilford does not recommend a pre-soak for FP4. They don't say whether it is detrimental, or just unnecessary. I don't see any mottling, but I did not look very close. I would try a sheet on a plain subject, like a gray card, or white paper (underexpose to make sure you don't get maximum density everywhere). A well-exposed sheet of a gray card is handy to have sometimes when calibrating exposures during enlargements, so it won't be a totally wasted sheet of film.

[mpirie]

I've often pondered why Ilford would say that a pre-wash was unnecessary for FP4. Maybe they have some surfactant mixed with the anti-halation layer that would be washed out in a pre-wash.

Personally, since most of my work is done on Jobo rotary processors, i think a pre-wash is essential to avoid uneven development. It has to help development since it soaks the emulsion, washes out the AH layer and makes the take-up of the developer more easy and consistent.

When I started with Pyro and FP4, i experienced mottled skies and banding at the film edge. I upped my pre-wash from 2 minutes to 5 and the problem disappeared.

Mike

[bgh]

Ilford does not recommend a pre-soak for FP4. They don't say whether it is detrimental, or just unnecessary. I don't see any mottling, but I did not look very close. I would try a sheet on a plain subject, like a gray card, or white paper (underexpose to make sure you don't get maximum density everywhere). A well-exposed sheet of a gray card is handy to have sometimes when calibrating exposures during enlargements, so it won't be a totally wasted sheet of film.

As Mike mentions below, I've never quite understood Ilford's recommendation re: presoaking. I can try some test negatives without the presoak, and see how it goes. And thank you for the suggestion about the gray card for a test negative, I will try that.

Thanks again!

[bgh]

I've often pondered why Ilford would say that a pre-wash was unnecessary for FP4. Maybe they have some surfactant mixed with the anti-halation layer that would be washed out in a pre-wash.

Personally, since most of my work is done on Jobo rotary processors, i think a pre-wash is essential to avoid uneven development. It has to help development since it soaks the emulsion, washes out the AH layer and makes the take-up of the developer more easy and consistent.

When I started with Pyro and FP4, i experienced mottled skies and banding at the film edge. I upped my pre-wash from 2 minutes to 5 and the problem disappeared.

Mike


Mike--
Thanks for your multiple suggestions. Yes, i am beginning to wonder if the Ilford just needs a different approach than what I've been using for years with the TMY. The other option is just to go back to TMY, since I've been getting consistent results for years. Its just so darned expensive! Especially for a volunteer project. I have a part of a box of TMY, though, and likely will try shooting an FP4 and a TMY negative of each view when I go out tomorrow, and see how things look.

Thanks again,
Bruce

[Jac@stafford.net]

Try skipping the pre-soak. Seriously.

[Mark Sampson]

How long is your usual development time? Are you using single-sheet hangers or the 4-up type? It's worth finding the Kodak publication "Photography with Large Format Cameras"; it has an excellent description of the exact technique required for developing in deep tanks with hangers. I've run sink lines in several labs, including at Kodak, and never saw unevenness like you have, so won't comment further. It is frustrating- but I'm sure you'll find the answer.

[consummate_fritterer]

To my eyes, the unevenness of density looks far too localized and random to be a processing issue. Are you absolutely certain you just didn't see the differentiation in the sky when you took the photos?

[Jac@stafford.net]

To my eyes, the unevenness of density looks far too localized and random to be a processing issue. Are you absolutely certain you just didn't see the differentiation in the sky when you took the photos?

I am now inclined to think there is no processing problem, nor an unevenness that would appear in an optical enlargement. If your posted images are from negative scans, look to your settings.

[HT Finley]

Looks like clouds to me.

[neil poulsen]

Do you see the mottling in the negatives?

I experienced this problem with HP5, and I came to the conclusion that my agitation was insufficient. My bad, I cut down on agitation, thinking that I was still within a proper range, to have more consistent negatives.

I'm doing dip-and-dunk using my own device (not the hangers), and I increased agitation to darn decent for the first minute (in-out ten times), and 10 seconds (or a little less; in-out 3 times) on each have minute (each 1 minute apart).

That increased agitation solved the problem.

[Fred L]

The third photo looks like it has uneven skies, the first two are very hard to determine tbh. I have no experience with Ilford films so can't offer much on that but as suggested, try no presoak and see of there's any difference.

[bw-man]

. ... ...then into the developer. Once in the soup, I agitate continuously for about 45 seconds (both up and down and forward and back), and then for 5 seconds every 30 ... ...

According to your instructions, I think the reason for the uneven film sky is that the stirring is too strong.
You can do it every minute, 5 seconds.Or stirring every two minutes for five seconds.
Black and white developer is too strong, not only film development is uneven.
The contrast of film, particle will have influence.
I don't know English, computer translation, probably not accurate.
This is my experience for your reference.

[Willie]

Why not try brush development? Pre soak for your time - 3 to 5 minutes. Then the negative emulsion side up in the flat bottom developing tray in the dark and a Hake or Richeson brush up and down, then back and forth. Then down and up and forth and back. Do it the whole time and be gentle. Should take care of uneven sky or large single tone areas.

Had to ask my Uncle as he develops this way. Uses FP4+ and it works for him on negatives in many sizes.

[Doremus Scudder]

There are limited possibilities here for a cause. Working through them should be fairly straightforward; no need to adopt an entirely new way of developing. Tanks and hangers have worked fine for generations. Nor do I think you can blame the developer.

Possible causes and suggestions:
1. Presoak is too short, or you don't need it at all. Try a significantly longer (min. 5-minute) presoak and try no presoak. FWIW, I presoak for 3+ minutes.
2. Agitation is insufficient or too vigorous. Test with different agitation schemes (although your agitation sounds just fine to me).
3. The film is defective. Try another batch or brand. Test develop a sheet in a tray after exposing under the enlarger, etc. to see if, indeed the film is the problem.
4. Some scanning problem. I have no experience here, so can't help with settings, but do inspect the negative carefully to ensure the problem is there before undertaking other measures.
5. There were clouds in the sky that you didn't notice at the time of exposure (look at the other areas of the negative and see if there is unevenness anywhere else but in the sky). If this is the "problem," then you need do nothing :)

Best,

Doremus