4x5 Black-and-White fogging/develpment/lightleak issue

[Chester McCheeserton]

Hello- I am having a maddening time figuring out what is causing the graying out of the clear areas near the center of my negative.

It's subtle, but I hope viewable in these scans.

101843101844101845101846

has anyone experienced this problem with 4x5 black-and-white before?

I develop in trays, 6 at a time, HC-110 stock solution diluted 1.75 oz to 30 oz water. Using a rotation method that I've used for years without a problem.

I use N-H-5 fixer diluted 6 oz to 26 oz water, no hardener. At first I was sure this problem was caused by lightleaks in my bellows, but I recently did the flashlight darkroom move and patched everything up so that I see no pinpricks of light at all with a flash light. There isn't a hard edge of the fog/graying it's subtle - the edges of the film are totally clear.

Could this be the result of inadequate fixing? I don't time the fix but rather count the rotations, it's likely 3 or 4 minutes. If it was a fixing issue would re-fixing help?

Could it be a light leak in my changing bag? Or slight fog from light spilling in past door in darkroom? Going kind of nuts here, the problem is semi-fixable in photoshop, but to go to all the trouble and expense to produce these to be able to print in the enlarger I need to figure out how to eliminate it.

It's not in every frame but in enough to drive me to make this post. It doesn't seem to ever show up in my color film (same camera, same changing bag) which leads me to believe the culprit it somewhere in my darkroom/processing routine.

Thank You for any thoughts or suggestions

[David Vickery]

Which lens are you using for these? And what camera?
Was it the same lens for each?
Is the center slightly out of focus also, or is it just more density?

Re-fixing will not help at this point. It is possible that you didn't fix enough and then fogged the film when you turned on the lights, or etc. but it sounds like, and looks like, you fixed enough so that this would not be caused by that. When you shuffle the film, do you give each sheet plenty of time to absorb the fix?

I had a similar problem one time and narrowed it down to a particular lens. It was odd. On mine the center of the film had slightly more exposure like yours, but it was also slightly out of focus as well.
A light leak any time after loading film holders would leave clear edges as long as the film is still in the holder when it happens.

It could be a flair problem within the camera that is exacerbated by a long lens or a lens with a large amount of coverage, image and non-image.

[Chester McCheeserton]

Schneider Apo symar 135 5.6 which is my workhorse lens bought new 15 years ago
Wista/zone 6 cherrywood field (looks like Wista DX models still sold, but has zone 6 plate on front)

Yes it was the same lens for each of the above, although I am posting one below taken with a 180 rodenstock where it's even more pronounced101848

I don't think the center is out of focus, just more density. I am pretty sure I give each film enough time to absorb the fix - been doing it this way for years.
I'm inclined to think you might be right about a flair problem within the camera, it seems likely that this is happening when I pull the slide and then wait for more than 5 secs to make the exposure. cars/birds/planes etc.

Thanks David, for your thoughts

[David Vickery]

That last one almost looks like a reflection off of the rear surface of the lens. I would look for a really small light leak near the rear of the camera, or anywhere really. I would also look for any surfaces inside the camera that are a little too reflective, but your comment that it seems to coincide with having the dark slide out for a longish time makes me think it may be a small leak.

[AtlantaTerry]

Here is a test to try.

From inside a house, aim the lens through the curtains and have a black fabric covering the bellows. Then try to simulate what you described above where you have the dark slide out for a while. Take a photo of whatever is available.

Develop as described.

Is the problem still there? If so it is the lens since the camera body itself was kept dark.

[Terry Christian]

I'd suggest taking your camera out into the backyard on a sunny day and with that lens in place, leave a piece of film for a long time (an hour or so?) with the darkslide out, but without opening the shutter. Develop as usual. This would see if you have any light leaks that could be small enough to barely make a difference during a normal exposure but that would show themselves with a long one.

If the problem was your fixer or length of time you leave film in your fixer, the negative would have an translucent-to-opaque, milky appearance.

[TimeShare]

I had a similar problem and the culprit was due to not giving the film a healthy presoak to remove the antihalation layer ... here is a link to my earlier post

http://www.largeformatphotography.info/forum/showthread.php?105937-Tray-developing-problem-8x10&p=1058420#post1058420

[AtlantaTerry]

Another idea: maybe the shutter is not closing absolutely completely.

I like Terry Christian's idea.

Also try this to test the shutter: take the lens into a dark room. Wait 5 or 10 minutes then shine a flashlight on the back of the lens while looking into the front. Move the lens a bit to possibly see light leaking through the shutter.

[Doremus Scudder]

I'm tend to also be in the light-leak camp, but there are other things to rule out here as well in your search for the culprit.

Just thinking out loud here:

If it were a particular lens, it would be a visible defect on one of the lens elements themselves such as damaged coating, really bad fingerprint, etc. BTW, I have a 135 Ektar with coating damage that causes almost precisely this kind of effect when photographing bright subjects. However, the fact that this fogging occurs with more than one lens kind of rules out a lens issue. That said, examine your lenses well just to make sure. Were you perhaps using the same filter? A filter with a defect or smudge might be the culprit.

Also, take a look at other negatives taken with other lenses, especially those with shadow (i.e., clear) areas in or near the center and see if they also have noticeable fogging; i.e., ascertain whether this is, indeed a fogging issue that happens with many different lenses. If you can narrow it down to two or three lenses, but have others that do not exhibit the fogging issue, you may be able to find a common problem such as a small light leak in the lensboards/mounting, etc.

Re-do your flashlight test leaving the back on and using the lensboard opening to introduce the flashlight, paying special attention to the back as well as the bellows and wood joints toward the rear of the camera. Extend the bellows fully and look at each of the folded corners. This might mean that you have to position your flashlight to shine into each corner. Sometimes flashlights can be too directional; you may want to do your test with a bare light bulb or a flashlight with the reflector/lens assembly removed. This often shows up small leaks that would otherwise go unnoticed.

Also look at the inside of the lensboards you have, shining a light in from the front in order to see if there are any leaks in the mounting. If you use after-market or homemade lensboards, there can often be a small mismatch that leaks light a bit. Examine the lens mount to the board and the board itself for leaks, unplugged screw holes, etc. while you are at it.

Examine the inside of your camera with the back on and a filmholder inserted, darkslide drawn, and with the light source behind the back for light leaks as well. While you are at it, look for any reflective areas facing the lens which might reflect light to the rear lens element and then back to the film.

I wouldn't rule out a fixing issue entirely either until I re-fixed one of the offending negatives just to make sure. Tray processing, especially when the agitation is vigorous, often results in the very center of the negative getting less developer/fixer activity.

I also like the sunny-day test Terry described above: set up everything, pull the darkslide and let the camera sit a good while but don't take the shot. Develop the unexposed neg to see if there is any center fogging. If so, it has to be a camera issue. I might also take two shots: a control neg with the bellows and back well covered with my dark cloth and pull the darkslide, immediately expose, and then quickly replace the darkslide on one neg, and one where I left darkslide out and camera exposed to light for a longer time. A comparison would show and difference. Choose a subject with dark shadows in the center of the image.

Sometimes you can correct the fogging defect when printing, if you use VC paper, by dodging the area up a bit during the basic exposure and then burning it back down later with much higher contrast filtration. Otherwise, some judicious retouching of the shadows in the print itself to introduce some really dark areas can be gratifying.

Good luck finding your problem,

Doremus

[Chester McCheeserton]

A very late Thank you for all the suggestions and tips. Never was able to pinpoint it exactly..tried Terry's sunny day test and couldn't see a difference. think Doremus' hunch about aftermarket lensboards may have been it, I put black tape over some odd indentations in the Bromwell boards, patched up a few more worn areas on the corner seams of bellows, and in general tried to cover the back of the camera with the darkcloth as soon as I pulled the darkslide.

Switched up to 5x7 recently and haven't noticed the problem (knock on wood) in b&w negs I develop the same way...so it prob was light leak.

[Jim Noel]

" in general tried to cover the back of the camera with the darkcloth as soon as I pulled the darkslide."
I learned long ago from Cole Weston to always have the bellows and back of the camera covered by the dark cloth. If my camera is mounted on the tripod,the dark cloth is covering everything but the lens. No exceptions.