Overexposed edges

[claytume]

I've been busy fixing some problems on my new camera, one was a light leak and I'm now confident I have it sorted out. So I shot off some film mainly to test some lenses but also to see if any other problems cropped up. The film is HP 5 and developer Pyrocat HD.

All the negs when contact printed show some extra exposure around the edges. The film holders are new and the only thing I can think may be doing this is reflections from the bare wood of the holder. I checked other film holders, Graflex, Fidelity, Lisco etc. and all exposed surfaces are painted black. All the wooden parts of the custom holders are not painted and left bare. This is a light coloured wood.

Anyone come across this problem before?

I'll test my theory by painting one side of the holder and exposing a sheet on either side and post the results.

Clayton

 

[bobfowler]

I think you may be right. Who made the holder?

 

[richard littlewood]

Could be edge build up during development. This happens with a lot of sheet film developing processes. How do you dev the film?

 

[Donald Miller]

I would think that it was a development procedural problem.

 

[Daniel Grenier]

I too use HP5 in Pyrocat. No such problem in processing (tray/brush).

You may want to consider that this is light bouncing off your bellows.

I would suspect your bellows are very close and tight to the film's edges(right?). Try shooting a smaller sheet of film in the very same conditions and you will prove (or disprove) this. You can do this by cutting a sheet down by 50% (in all directions) and taping in the center of one holder with a full sheet on the opposite side of the holder. Shoot both sheets in the exact same manner. Process both identically and I would bet the small sheet does not suffer from this. Why? Because light bouncing off the bellows is just too far from the smaller sheet of film to be of concern.

Just a thought. Good luck solving this and when you do, let us know.

 

[juan]

I think it's a development problem, too, rather than an exposure or light leak problem. As others have asked, how are you developing?
juan

 

[Allen Friday]

I use S&S holders in my ULF cameras. They are light colored and I had problems similar to the one you have. I finally painted the edges of all the holders with flat black craft paint and that took care of most of the problem. If you do not have much room around the holder for the bellows, you may still get some extra edge density, but not as much as the posted photo shows.

 

[claytume]

I think it's a development problem, too, rather than an exposure or light leak problem. As others have asked, how are you developing?
juan

Juan

I'm using a Jobo processor and the film is sitting in a reel tank. I've processed lots of sheet film like this of various odd and standard sizes and never seen extra edge density like this. I will go and check so old negs though just to make sure.

Clayton

 

[claytume]

I use S&S holders in my ULF cameras. They are light colored and I had problems similar to the one you have. I finally painted the edges of all the holders with flat black craft paint and that took care of most of the problem. If you do not have much room around the holder for the bellows, you may still get some extra edge density, but not as much as the posted photo shows.

Allen

how wide would you estimate the extra edge density was? On my negs it's 3-4mm on the long side.


Clayton

 

[sanking]

Allen

how wide would you estimate the extra edge density was? On my negs it's 3-4mm on the long side.


Clayton

INHO there is no way that reflections from the bare wood are going to cause extra density of 3-4mm into the film area. I looked at your sample carefully and in my opinion that much extra density simply can not be caused by reflections off the wood.

Painting the edges of the exposed holders black may reduce flare slighlty when shooting in very contrasty situations into the light. However, I have personally not found any difference at all in results in my own work between bare wood and painted surfaces.The edges of my own 12X20" holders are painted black, but edges of my 7X17" ones were left bare. I have yet to see any difference in edge density between the two types.

Should any owners of S&S holders feel strongly that the edges of the internal bare wood need to be painted black we will be happy to do that. Or, if you already have a holder and are willing to do the work yourself it should take only about a minute or so per holder. What I would recommend is that you use a permanent felt marker (one good brand for this here in the USA is Marks-A-Lot), black color of course. Put a piece of discarded film in the holder, and simply blacken the inside of the holder with the marker. I have found this much easier to do than masking the holder and spray painting.

Sandy

 

[claytume]

Could be edge build up during development. This happens with a lot of sheet film developing processes. How do you dev the film?

Richard

it isn't a development problem. I had a look through a number of negs of a similar shape and size shot on another camera and developed with the same developer and same processing equipment. Every one was perfect around the edges.


Clayton

 

[claytume]

INHO there is no way that reflections from the bare wood are going to cause extra density of 3-4mm into the film area. I looked at your sample carefully and in my opinion that much extra density simply can not be caused by reflections off the wood.

Sandy

Sandy

I'm now down to one of two things or a combination, I've ruled out development problems after carefully inspecting similar negs shot on another camera and processed with the same equipment.

So the 2 things left are light bouncing off the bellows/lack of room around the holder and reflections off the holder.

The 3-4mm I mentioned earlier is wrong, my fault, just a guestimate. I've just measured it properly and it's in the 1-2mm range so not as bad as originally stated.

Clayton

 

[sanking]

Sandy

I'm now down to one of two things or a combination, I've ruled out development problems after carefully inspecting similar negs shot on another camera and processed with the same equipment.

So the 2 things left are light bouncing off the bellows/lack of room around the holder and reflections off the holder.

The 3-4mm I mentioned earlier is wrong, my fault, just a guestimate. I've just measured it properly and it's in the 1-2mm range so not as bad as originally stated.

Clayton

Clayton,

This is obviously a very vexing thing, but I am not at all sure that the problem has been reduced to one of two things you suspect. In fact, I believe there still exists a strong possibility of light leaks caused by fit between the holder and back.

I agree that the problem is most likely not development. The uneveness is simply too great. For the same reason I don't believe it is light bouncing off the wood of the holders. The lack of eveness in your sample is much too great for that as well, IMO.

In some high contrast lighting situations it is possible that the light leaks might be caused by light reflecting off the bellows, but your sample shows more uneven density that I would expect even with an an extreme example of light reflecting off the bellows.

You could resolve the question by completely wrapping your camera in a black cloth or tent when you insert the film holder and make the exposure. If you do this and still get areas of uneven density on the negative you can be sure that the problem is one of the following: 1) bellows or camera leak, in front of the back, 2) light reflecting off the bellows, 3) light reflecting off the holder, or 4) some combination of the above. If, on the other hand you do this test and the negative is evenly exposed and developed, the problem is most probably due to fit between the holder and camera.

Failing any of the above there are problems that could take place out of the camera, as in loading, unloading, and developing.

Or perhaps the cause is none of the above. So I will say to you, as Lewis Carrol wrote a long time ago in Alice in Wonderland, "I weep for you," the Walrus said. " I deeply sympathize."

Sandy

 

[George Losse]

Clayton,

Most of the density problems in the print you posted look they are development based, not camera or holder based.

After you make the exposures tell us what happens to your negatives next.
Do you unload into a holding box, an empty film box? Do you unload straight from the holder into the tank for processing?

I had problems with Ilford boxes before that were not really light tight. I could see the outline of the sheet on top notch pattern in lower films. This I solved that problem by keeping exposed films in opaque black plastic bags inside the film boxes. Most of the low cost film's boxes are not very good either.

The holders are newer holders like S&S? That would rule out any problems with the dark slides not being opaque.

You didn't mention at what speed your processing the film either. I have seen edge density build up from running the jobo at too high a rotation speed. This is more of a problem with the 2800 series print tank because of the plastic ridges inside the tank causing turbulence in the chemistry.

 

[noseoil]

Clay, looking at the image on my monitor, it appears that the edge of the film beneath the film holder's edge has had some exposure as well (I'm ruling out film speed as a problem in the print density). It looks like a pre or post exposure problem, not an in-camera problem. The edge is too uniform and looks to be pretty even. For all we know, the film batch could be the problem. Where did it come from? Did you try processing a sheet without any exposure to see what is there? It has to be something simple, based on your obvious knowledge of film and processing. tim

 

[claytume]

Clayton,

Most of the density problems in the print you posted look they are development based, not camera or holder based.

After you make the exposures tell us what happens to your negatives next.
Do you unload into a holding box, an empty film box? Do you unload straight from the holder into the tank for processing?

The holders are newer holders like S&S? That would rule out any problems with the dark slides not being opaque.

You didn't mention at what speed your processing the film either. I have seen edge density build up from running the jobo at too high a rotation speed. This is more of a problem with the 2800 series print tank because of the plastic ridges inside the tank causing turbulence in the chemistry.

George

As I was only shooting tests the film remained in the holders until I got back to the darkroom. From there they were loaded directly into the film tank.

The tank I'm using is for film reels and has smooth sides, forget what # it is but it isn't an expert tank.

I rotate the tank at 3 1/2 (I think) for 30 seconds then drop the speed back to the slowest speed, this is a CPP processor.

Yes these are brand new holders. For now I prefer not to divulge the brand of camera or holders (both are new) as I don't want to stir up any negative sentiment for either when all I have at this stage is pure speculation. Afterall it could be something dumb I've done myself and I know we've all been in that boat at some stage.

Keep the ideas rolling!

cheers
Clayton

 

[claytume]

Clayton,

This is obviously a very vexing thing, but I am not at all sure that the problem has been reduced to one of two things you suspect. In fact, I believe there still exists a strong possibility of light leaks caused by fit between the holder and back.

In some high contrast lighting situations it is possible that the light leaks might be caused by light reflecting off the bellows, but your sample shows more uneven density that I would expect even with an an extreme example of light reflecting off the bellows.

You could resolve the question by completely wrapping your camera in a black cloth or tent when you insert the film holder and make the exposure. If you do this and still get areas of uneven density on the negative you can be sure that the problem is one of the following: 1) bellows or camera leak, in front of the back, 2) light reflecting off the bellows, 3) light reflecting off the holder, or 4) some combination of the above. If, on the other hand you do this test and the negative is evenly exposed and developed, the problem is most probably due to fit between the holder and camera.

Failing any of the above there are problems that could take place out of the camera, as in loading, unloading, and developing.

Or perhaps the cause is none of the above. So I will say to you, as Lewis Carrol wrote a long time ago in Alice in Wonderland, "I weep for you," the Walrus said. " I deeply sympathize."

Sandy

Sandy

now I've had another think about it and read your post I tend to agree that I haven't narrowed it down to 2 problem areas. So I will look further into your suggestions.

I'm starting to think it may be a back leak problem, read on and I'll tell you why.

This is the third camera I've had a light leak problem with, all were either late model or new. All are panoramic cameras, the first 2 are rotating cameras. They both took endless time and testing to find the problem.

The first camera I decided to modify and upgrade it's performance. I sent it to a specialist in California, he did the work, tested it, sent me the negs, I ok'ed it and he shipped the camera back. First time I used it I had a bad light leak, both the guy in California and myself were dumbfounded. I had in my hands the test negs shot on a bright sunny day and they were perfect.

Eventually I found the leak and we deduced the only reason it leaked here in New Zealand was the very bright low angle light hitting it in a certain position every time I used it. Appears bright sunny days in California are no match for the bright light we get here.

Camera #2 was bought used but in mint condition from Florida. Seller stated the camera was flawless and he had never had any problems whatsoever with it. When I received it, it was indeed in the condition decribed, I couldn't find a mark on it.

First negs I shot had a light leak on it.........here we go again! Same story, the seller had proof the camera worked flawlessly.

This one took a long time to find the problem and when I found it, it was directly related to the bright low angle light we get here. An overcast day was no problem.

So I'm thinking Sandy might be onto something here and it may be a back leak problem. I'll test that next and let you guys know.

Clayton

 

[ras351]

Hi Clayton,

I really don't know quite what to suggest other than trying to reduce the possibilities as Sandy suggests. Using photographic paper might be a cheaper/easier option than film but you'll need to flash it slightly before loading so it's sensitive to small light leaks. If you use film photographing a gray card or something similar might make it easier to see density changes as will slightly overdeveloping. What time of day was the harbour picture taken and where was the sun located in reference to the camera?

Regards,
Roger.

 

[claytume]

Clay, looking at the image on my monitor, it appears that the edge of the film beneath the film holder's edge has had some exposure as well (I'm ruling out film speed as a problem in the print density). It looks like a pre or post exposure problem, not an in-camera problem. The edge is too uniform and looks to be pretty even. For all we know, the film batch could be the problem. Where did it come from? Did you try processing a sheet without any exposure to see what is there? It has to be something simple, based on your obvious knowledge of film and processing. tim

Tim

yes this film isn't perfect, it's outdated (1999) HP5 a friend gave to me for testing. When developed it has a very high base fog.

The reason I'm using it is I don't have anything else that will fit. I ordered some custom cut Ultrafine some time back and still waiting which sounds like a problem others have as well.

Clayton

 

[claytume]

Hi Clayton,

I really don't know quite what to suggest other than trying to reduce the possibilities as Sandy suggests. Using photographic paper might be a cheaper/easier option than film but you'll need to flash it slightly before loading so it's sensitive to small light leaks. If you use film photographing a gray card or something similar might make it easier to see density changes as will slightly overdeveloping. What time of day was the harbour picture taken and where was the sun located in reference to the camera?

Regards,
Roger.

Hi Roger

I used photo paper when I was working through the first lot of light leak problems I had with the camera. I did it because I have a tiny supply of film (am waiting for fresh supplies) and I have plenty of rolls of paper and a paper dispenser. So it's a very easy job to cut/shoot/process with quick feedback.

I checked those paper negs and they don't show extra edge density but then they're very high contrast as well. So I will try flashing some and giving it another go. Much easier to test next to the darkroom!

The harbour photo was taken with full bright sun about 2pm. The sun would've been at right angles to the camera or slightly behind. Probably an ideal place for any leaks to show up through the back.

Clayton

 

[claytume]

Hi Clayton,

I really don't know quite what to suggest other than trying to reduce the possibilities as Sandy suggests. Using photographic paper might be a cheaper/easier option than film but you'll need to flash it slightly before loading so it's sensitive to small light leaks. If you use film photographing a gray card or something similar might make it easier to see density changes as will slightly overdeveloping. What time of day was the harbour picture taken and where was the sun located in reference to the camera?

Regards,
Roger.

I did some testing in full sun using photo paper in the holders. It appears to be a light leak problem in the camera back. I did a lot of tests and found it was hard to replicate the situation where the leak shows up and I suspect bright sunlight does it as certain angles to the back.

The photo clearly shows a leak and the left side and bottom edges have slightly more density.

Clayton

 

[ras351]

Hi Clayton,

Bother You shouldn't be having these sorts of problems with new holders. Unfortunately paper is less sensitive than film so it takes longer but at least it's shown a problem. If there doesn't seem to be anything obvious and all the light traps seem okay it'd be worth checking that everything is straight and true. You can sometimes spot a warp with the eyeballs. If not trying placing the holder on some flat glass or something similar (hanging it over the edge as necessary to clear the lip) and tapping each corner to see if there's any movement. If something wobbles rotate it 90 degrees and test again to make sure the glass is actually flat. If the same corner wobbles the holder is probably warped. It's also worth checking the camera back in a similar way if possible. Also run a straight edge along everything (camera back included) and hold it up to the light to make sure you can't see a gap and that it's all straight. If everything turns out okay we'll have to dig further.

Let us know how you get on.

Regards,
Roger.

 

[claytume]

Hi Clayton,

Bother You shouldn't be having these sorts of problems with new holders. Unfortunately paper is less sensitive than film so it takes longer but at least it's shown a problem. If there doesn't seem to be anything obvious and all the light traps seem okay it'd be worth checking that everything is straight and true. You can sometimes spot a warp with the eyeballs. If not trying placing the holder on some flat glass or something similar (hanging it over the edge as necessary to clear the lip) and tapping each corner to see if there's any movement. If something wobbles rotate it 90 degrees and test again to make sure the glass is actually flat. If the same corner wobbles the holder is probably warped. It's also worth checking the camera back in a similar way if possible. Also run a straight edge along everything (camera back included) and hold it up to the light to make sure you can't see a gap and that it's all straight. If everything turns out okay we'll have to dig further.

Let us know how you get on.

Regards,
Roger.

Hi there Roger

I'm sure it's a problem with the camera back and not the holders. And it only happens with the sun at certain angles. About a month ago I tested the holders and camera in bright sun with photo paper in the holders, everything tested fine that time.

I have also shot some film in overcast conditons with no problems.

As I mentioned earlier I have had leak problems with other cameras, it's slow and frustating working through it. The good part about it is you get to know every inch of your equipment!

Tomorrow I'll run a straight edge over everything and let you know how it goes.

cheers
Clayton

 

[noseoil]

Clay, when hanging French or double doors, two strings are used from corner to corner when the jams are set in place. If the strings touch gently, everything is good and the jams are nailed. If there is a gap between the strings (threads in this case) or they push on each other, the legs are out of plane and must be adjusted. This may help to check the back's flatness. You might also check with a feeler gauge and a sheet of glass to see if the back is truly flat. Good luck and sorry it wasn't the film. tim

 

[George Losse]

Clayton,

I hate too break this to you, but your test does not indicate the cause of the edge density build up as shown in the first attached negative. It shows a light leak in a holder possibly caused by putting pressure on the dark slide while handling the holder. This paper test was not processed under the same conditions that the negatives were.

You can spend all the time you want chasing film flatness, holder squareness, and weather the back is square...... those things can be answered by taking the spring back off the camera and inserting a holder into the back. Any possible light leak will show up as a location where the holder does not sit flat on the spring back. Most of the time the problem is at the location where the bar on the holder goes into the groove on the spring back.

After you get done with that, you'll still have the edge build up on the negatives, because its most likely from turbulence of the chemistry on the film in the development tube.

I think your spinning the tank too fast during processing. I've seen the same thing on 8x20 negatives I've processed. It went away when I turned the speed on the processor down as far as I could and still kept it moving.