Light leak - driving me mad for weeks

[MikeOates]

So my first post here, and sorry it's a problem.

Here is a 4x5 negative (FP4+) and I keep getting these light leaks, they are never the same, but always at the top (trap end of the holder).

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The leaks can be full width of the neg and as you can see it looks like its getting fogged before or after being in the film holder. I thought I had tracked it down to possibly getting light in my Calumet Film Changing Room/tent. So I did two things, loaded the holders/tank in a Paterson film changing bag (Great no fogging) then added an extra elasticated strap to the arms of the Calumet tent so each arm hole now has two restrictions instead of just one. And for bolt and braces also covered the tent in black cloth. I always do this is a room with no lights on with curtains closed, not dark, but no strong light. For a few sessions ( 6 or so negatives) no fogging :), then I got this one. The other neg on side b of the same holder was loaded up and put in the tank at the same time and that was fine.

I can't track it down to any film holder, I have 6 and it can happen to any. The tank is the Stearman Press SP-445, and I have 2 of these, again no correlation with which tank used.

Is it possible to get fogging like this from faulty film holders, I can't see it, as I said I have 6 of them and are all new Toyo holders. The camera is a Cambo Legend, used indoors. Tried different bellows, checked for leaks etc.

Can anyone help ?

Thank you,

Mike

[Corran]

I think you can rule out film holders because your top rebate wouldn't be fogged like that if it was your holders. But, you could do some systematic testing to check. Perhaps buy some cheap x-ray film to use instead of "real" film.

I don't use tents or the Stearman tank so I'll let others comment on that.

BTW nice gears, crop the top off and you've got a good photo still :).

[C. D. Keth]

When you load your tank, do you load so that the notched end of the film is up in the tank?


Sent from my iPhone using Tapatalk

[Vaughn]

You can see the 'shadow' of the notches of one piece of film cast onto the negative you showed us (upper right side). One neg was laying cross-wise on the other when the light snuck in. While loading or unloading the holders, probably...or while getting ready to develop.

But it should not be a 'shadow' -- but a clue nevertheless!

Sorry...having too much fun...back to the two negs laying on top of each other: the light gets 'piped' in between the two sheets of film from the edge -- but does not get piped in where the notch is because there is no film there...thus no exposure where the notch is. Note that the upper right corner of the film is not exposed -- measuring the distance, this corner is right where the second big notch of the top piece of film would be -- and no piping of the light.

And from the looks -- more than two sheets of film involved.

So your holders and camera are good to go. Look elsewhere for the leak.

[Willie]

"Trap end"? You mean the top where the dark slide inserts? Or the bottom(as the film holder inserts in the back) where the flap is for loading the film?

[Peter Mounier]

I wonder whether you have a reflection inside the bellows striking your film as you're making the exposure. I inverted your negative image to view it as a positive, then put a curve adjustment on the light leak to increase the contrast enough to find the hotspot. The light leak doesn't seem to be as bright at the edges, as expected, but seems to be in the center of the light leak. If it were brighter at the edges you could assume the light was coming in from outside the film holder and dissipating as it spread across the film. Here it seems to dissipate outward in all directions from an area in a bit from the edge.

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[Fred L]

process a sheet straight from the box, which may or may not be the problem. is it bagged or double boxed ?

[Gary Beasley]

Looks like a pinhole in whatever the film was in, the box it came still in good shape?

[MikeOates]

Wow! thank you all very much, lots of pointers there for me to look at. Rather than post lots of separate replies I will do a single recap one here...

[Corran]
>I think you can rule out film holders...
Yes that is the conclusion I thought as well.

[Chris]
>When you load your tank, do you load so that the notched end of the film is up in the tank?
Yes I do.
Also the fact that two negs developed together in the same tank should rule out the tank, plus as I said I have used 2 tanks.

[Vaughn]
>...back to the two negs laying on top of each other...
Never at any time were two negs on top of each other, I take one out of the box at a time, the rest never leaving the folded card that covers the film sheets.

[Willie]
>"Trap end"? You mean the top where the dark slide inserts? Or the bottom (as the film holder inserts in the back) where the flap is for loading the film?
Sorry wrong terminology, I mean the flap end where the film is loaded.

[Peter]
>I wonder whether you have a reflection inside the bellows striking your film as you're making the exposure
I did have that effect early on, took me a while to realise what was happening, no it's not that, I now check for brighter areas outside the image area and either use a lens hood, and or I mask off those areas with flags, black cloth etc actually around the subject I am shooting.
Your other point:
>The light leak doesn't seem to be as bright at the edges, as expected
I think this is just the effect of the image area receiving the image photons plus the light leakso that exposes the film more in those areas.

[Fred]
>process a sheet straight from the box, which may or may not be the problem. is it bagged or double boxed ?
I tried that early on and it was ok, film is bagged and boxed, the example above is double boxed.

[Gary]
>Looks like a pinhole in whatever the film was in, the box it came still in good shape?
No this is happening from 3 different boxes & two different film typs (FP4+ and Foma 100)


Recap: So it looks like I can rule out a camera or film holder problem, and it looks like 'operator error' in someway, when I am either loading the film holders, or taking film out of the holders and straight into the developing tank. I have not been storing exposed negs in a box.

Just to add more info in case it helps, all the exposures are quite long, in the order of 30 sec to 5 mins as they are taken indoors, low light levels and small apertures.

From the pattern on the right hand edge, I thinking along the line of I may be pausing slightly with the film almost in the holder because there is a repeat shadow whch I have marked on one of the negs below.

I also add a few more negs to show the variation. If this is happening while loading/unloading the film holder, I am very surprised that this can happen when I have gone to extra lengths to make the changing tent more light tight.

Thanks again for your observations.

Mike
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[Willie]

How well do the film holders fit in the back of the camera? It appears you may be getting light leaks at the bottom. Causes could be poor fit, you not having the holder in fully or not tight at the bottom. Maybe not enough spring pressure at the bottom and somehow you are pulling and inserting the darkslide and causing the bottom to move. Pushing into the back when removing and replacing the dark slide might help here.

How well does the back fit on the camera? Check that for any leaks. Since they are all coming from the same end it is a process of elimination.

For now, when you put the holder in the camera do the "Morley Baer wrap" around it with the dark cloth and make sure you have the bottom area covered well.

[Vaughn]

Gave it my best shot! Good Luck!

[jonby]

Some of the marks at the right edge seem to conform to shadows that would be cast from the tabs on the Stearman Press holders. There are different versions of the holders though - have you checked to see whether there is any possible correlation with your tank holders and the light leaks? Is there any possibility of light strikes when the film is in the tank holders but before you put them into the tank? However, with all the leaks being towards the top, this suggests that they are happening whilst in the tank - either before the lid is put on, or leaks during processing. The curved horizontal band in the fourth neg does suggest the curvature of the Stearman tank.

Do you always put the film with the notches at the top of the tank? Maybe try putting the notches at the bottom, and if your next light leak is on the other end of the neg then that would offer some clues.

I hope you solve it. These would have been really nice images.

[MikeOates]

Oh boy that was a bit of a pain to test lots of ideas out, but after sacrificing 6 more sheets of film, I now have the reason for the light leaks/fogging, please read on.

So last night I took 4 films and treated them as follows... (6a etc. means film holder 6 side A)


6a: Loaded a film from the box taking my time (about 2 mins before it went in the film holder), this was to test the light tent. I did not expose this, but it went in the camera when taking 6b.

6b: Normal handling, took a photo about 3min exposure.

1a: Normal handling, took a photo about 3min exposure, but covered the camera with the dark cloth.

1b: Just as 6b, but I put the film in the holder upside down.


In all cases I was careful to make sure the holder was not moved when pulling out the dark slide.

I developed all these together in the SP-445 tank, and... all were perfect! by perfect I mean no light leaks, the photos were of nothing, I just wanted to go through the motion.

So where did I go from there, well I read jonby's post where he says "Some of the marks at the right edge seem to conform to shadows that would be cast from the tabs on the Stearman Press holders"
I decided to put the developed negatives back in the holders and lo and behold, the marks lined up! I would never have thought of this, I assumed that the tanks were light tight, well certainly light tight enough to handle in normal room light.

So to test this out, I sacrificed another 2 sheets of film, I have been using Fomapan 100 for this, the cheapest I have to hand. I put one sheet of each straight from the film box into into each tank. Then put the tanks on the windowsill in full sunlight for a minute. Developed as normal, and the results are below.

202301 202302

One is worse than the other, that came from the tank where the lid did not quite close as well as the other.

Where do I go from here? do everything as I was doing but keep the tanks out of any kind of light and for the minimum of time. I sometimes loaded the tank and developed hours later. I never left them in the light, but they weren’t in the dark either, so from now on they will stay in the light tent till I am ready to develop. I have to say I do like the Stearman SP-445 tanks, very easy to load, handle and they use a small amount of solution, I will just have to be more careful in future. I could also use some black PVC tape around the joint when the lid is one just to be sure.

It's taken weeks to sort out, about a full box of 25 sheet film wasted, but within 2 days of posting here, I got enough support to work it out. So I great big THANK YOU to all who contributed.

Mike, [ much happier now :) ]

PS: The reason for last night test of 4 film sheets was ok, was that it was late evening, not much light about and I developed them right after taking them.

[Bob Salomon]

Oh boy that was a bit of a pain to test lots of ideas out, but after sacrificing 6 more sheets of film, I now have the reason for the light leaks/fogging, please read on.

So last night I took 4 films and treated them as follows... (6a etc. means film holder 6 side A)


6a: Loaded a film from the box taking my time (about 2 mins before it went in the film holder), this was to test the light tent. I did not expose this, but it went in the camera when taking 6b.

6b: Normal handling, took a photo about 3min exposure.

1a: Normal handling, took a photo about 3min exposure, but covered the camera with the dark cloth.

1b: Just as 6b, but I put the film in the holder upside down.


In all cases I was careful to make sure the holder was not moved when pulling out the dark slide.

I developed all these together in the SP-445 tank, and... all were perfect! by perfect I mean no light leaks, the photos were of nothing, I just wanted to go through the motion.

So where did I go from there, well I read jonby's post where he says "Some of the marks at the right edge seem to conform to shadows that would be cast from the tabs on the Stearman Press holders"
I decided to put the developed negatives back in the holders and lo and behold, the marks lined up! I would never have thought of this, I assumed that the tanks were light tight, well certainly light tight enough to handle in normal room light.

So to test this out, I sacrificed another 2 sheets of film, I have been using Fomapan 100 for this, the cheapest I have to hand. I put one sheet of each straight from the film box into into each tank. Then put the tanks on the windowsill in full sunlight for a minute. Developed as normal, and the results are below.

202301 202302

One is worse than the other, that came from the tank where the lid did not quite close as well as the other.

Where do I go from here? do everything as I was doing but keep the tanks out of any kind of light and for the minimum of time. I sometimes loaded the tank and developed hours later. I never left them in the light, but they weren’t in the dark either, so from now on they will stay in the light tent till I am ready to develop. I have to say I do like the Stearman SP-445 tanks, very easy to load, handle and they use a small amount of solution, I will just have to be more careful in future. I could also use some black PVC tape around the joint when the lid is one just to be sure.

It's taken weeks to sort out, about a full box of 25 sheet film wasted, but within 2 days of posting here, I got enough support to work it out. So I great big THANK YOU to all who contributed.

Mike, [ much happier now :) ]

PS: The reason for last night test of 4 film sheets was ok, was that it was late evening, not much light about and I developed them right after taking them.

Now contact the manufacturer of the tank. Tell and show them the problem and ask them how they will solve it and make you whole for the loss of time, film and effort due to the problem.

[esearing]

I have 5 of the SP445 tanks and not one of then exhibits the problems associated with your light leaks. I assume you have assembled the thing with the 3 baffles alternating the openings and have the manufacturers lids and o-rings. The tab marks on the side of the film indicate you aren't cleaning your tanks film holders well enough or you have residue from using photoflo in the tank and have nothing to do with fogging. Don't take the lid off for washing until after you have fully fixed the film and started the washing process for a couple of minutes (NO peeking).

I am betting at some point your film was fogged in the box, maybe during the loading of holders and just a bit of light hit the top edge of the film. I managed to do that with a new box of Bergger 400 by flipping on the light too early and film was in the open ended black plastic bag , not back in the box yet. Every image from that box has some light exposure at the notch end. I think of it as my 4x4 film cause I know I have to crop it.

[richydicky]

Good perseverance and detective work and chimes with an experience I had but had forgotten about. Last year I was working abroad on a project using a number of different formats. Once, I put an exposed sheet in an SP-445 tank and it was at least day or day two before I loaded more and developed. I noticed that the sheet I had initially loaded had some odd light leaks and figured they must have come from the when it was in the tank. I meant to contact Stearman but was extremely busy so it passed by but did make a mental note not to do load and delay again. I rotary process mostly at home so it was only reading this that jogged my memory.

I was always concerned that the top is slightly bowed so never fits quite flush with the tank. I did mention this to them straight after I bought it but was assured that it was normal and OK. I have had to move the O ring around now as it started to leak a little so maybe that could a source. Will follow with interest any developments.

Richard

[Bernice Loui]

Penny wise, pound foolish.

No possible way anyone could talk or sell me on any of this darkroom stuff unless the stuff has a LONG proven history and record of doing what it must do.. and the particular sample of the darkroom item must be tested to the best of it's ability to prove it does precisely what it must do.

Consider the time wasted, effort wasted, film wasted, travel wasted, images lost, emotional stress caused by what happened.

Was all that and more worth the $ saved?

Second real test, what will be the manufactures response to these problems? While zero they can do now to compensate for the lost time, resources and images. how you're treated will tell a whole lot about this manufacture and brand.


Personally, my tolerance for this kind of non-sense is zero. After doing this sheet film stuff for a few decades, the tolerance level for failures like this is extremely thin as there is just too much to risk with anything less than total reliable - predictable.

For working photographers back in the days when sheet film color transparencies were it, stuff like this might happen once with an absolutely furious client that will never see you again and the odd of being struck as fail is high.

Save a bit now, or draw out the actual cost of failures over the long run with continued problems... It is a choice.



Bernice




So to test this out, I sacrificed another 2 sheets of film, I have been using Fomapan 100 for this, the cheapest I have to hand. I put one sheet of each straight from the film box into into each tank. Then put the tanks on the windowsill in full sunlight for a minute. Developed as normal, and the results are below.

202301 202302

One is worse than the other, that came from the tank where the lid did not quite close as well as the other.

Where do I go from here? do everything as I was doing but keep the tanks out of any kind of light and for the minimum of time. I sometimes loaded the tank and developed hours later. I never left them in the light, but they weren’t in the dark either, so from now on they will stay in the light tent till I am ready to develop. I have to say I do like the Stearman SP-445 tanks, very easy to load, handle and they use a small amount of solution, I will just have to be more careful in future. I could also use some black PVC tape around the joint when the lid is one just to be sure.

It's taken weeks to sort out, about a full box of 25 sheet film wasted, but within 2 days of posting here, I got enough support to work it out. So I great big THANK YOU to all who contributed.

Mike, [ much happier now :) ]

PS: The reason for last night test of 4 film sheets was ok, was that it was late evening, not much light about and I developed them right after taking them.

[C. D. Keth]

Sounds like you should consider those "very subdued light tanks" rather than "daylight tanks."

[jonby]

It does seem very likely from your results that your problems have been caused by light leaks in the tanks during processing. I can't agree with esearing that the tab marks have nothing to do with fogging, though I think his advice about checking that you have put the tank parts together properly is sound. I have never used one of these tanks, so I don't know what the pitfalls are.

However, now you are 90% sure what the problem is, you should be able to avoid it in future. You said it yourself: "PS: The reason for last night test of 4 film sheets was ok, was that it was late evening, not much light about and I developed them right after taking them." So the chances are that if you keep the tank in darkness up until you are ready to develop, and develop in conditions a bit dimmer than you had on that occasion, you should avoid further problems.

Of course, it is a shame that it has taken so long and so much work to diagnose this problem, but my take on this is that it has not all been wasted effort. My experience has been that machines and complex tools, including photographic gear, are rarely perfect; and it doesn't matter how highly regarded they are or how much you spend - there will always be some kind of problem at some point. And when that problem arises, you will need the kind of skills you have learned by working through this problem to solve it. If you hadn't gone through this process, you might have spent a fortune in time and money changing your camera, holders, film, working methods etc. Instead, as well as some ruined film, you have the very valuable experience of having worked through a problem to its conclusion.

Hope to see some perfect negatives soon!

[MikeOates]

Light Leak Update: Solved...

After a few emails with the manufacturer of the Stearman SP-445 tank, and to get to straight to the point, I was not closing the lid well enough and light was getting past the O-ring seal.

I had pushed the lid on as far as I could and I thought the slight gap was normal. What I did not realise was that the O-ring was too dry. Now I don't mean it was not wet, I mean it was not lubricated. O-rings should be lubricated with Silicone grease, or, as I did not have any, Vaseline. So I removed the O-ring, applied a very small amount of Vaseline and wiped it off again so there was no apparent Vaseline remaining. Put the ring back on and the top now seated very well and very easily.

Took a photo, developed and no light leaks.

The use of the lubrication is on the products website, I just never thought I was having a problem. Because as I said before, I was looking at possible light leaks from everywhere except the developing tank! The lubrication only needs adding occasionally, and may last a number of cycles before needing to be reapplied.

So problem solved. :o

Mike

[jonby]

Great to hear you have solved the problem. Probably best to keep developing in subdued light though, just in case.

[Bill Poole]

This is good information, Mike. I have one of these that I use when I have only 4 sheets to process, and will keep an eye out for this issue. But in general, I have been happier with the MOD54 reels in the Patterson tanks, which are time-tested and seem more natural to use for me. It takes a little longer the learn loading of the MOD54 reels, but then it's a breeze. I have two reels and two tanks, so I do a dozen films at a time once I am set up to process. Thanks again for the heads up on the Stearman tanks.