Is it possible that a 4x5 film cassette is leaking light?

Frank53 · Jan 29, 2022

Sometimes my negatives show obvious light leaks. I checked the bellows in the camera under a very strong light. Nothing wrong there. Looking at the construction of the cassettes, I can hardly imagine that any leaks happen there, but maybe I’m overlooking something. I bought quite a lot of them second hand.
if this is not possible, it must be something in the way I work, filling the cassettes with film, exposing the film, putting the film in the developping tank….

BrianShaw · Jan 29, 2022

Hi Frank. Yes, it is possible to have light leaks on 4x5 film holders… mostly at either the flap of dark slide. Old wood holders can warp causing leaks too.

More details will help. What kind/brand of film holder? What camera? Picture of your light-leak negative. What processing equipment? Description of your film handling process ?

Sounds like a lot of information but the e more you give, the more meaningful feedback you’ll get.

Nitroplait · Jan 29, 2022

A picture of the full negative is the minimum requirement as a startingpoint to troubleshoot lightleaks.

Frank53 · Jan 29, 2022

BrianShaw said:
Hi Frank. Yes, it is possible to have light leaks on 4x5 film holders… mostly at either the flap of dark slide. Old wood holders can warp causing leaks too.

More details will help. What kind/brand of film holder? What camera? Picture of your light-leak negative. What processing equipment? Description of your film handling process ?

Sounds like a lot of information but the e more you give, the more meaningful feedback you’ll get.

I could make a picture of the negative, but at the moment I have scans of 2 negatives that come from the same filmholder. One has a leak right upper side, the other right under, which is not strange imo because the holder is turned for the next picture. I made 4 pictures at the same spot, but those have no signs of a leak.
The camera is a Tachihara, which I got last week, but the same happened with my Linhof occasionally. Those are shots to test the camera.
The films are developed in SP-445, just following normal instructions.

BrianShaw · Jan 29, 2022

Check your film holder for warpage. Also consider the possibility that when pulling the dark slide that you inadvertently jiggled the holder from the back causing light hurt leak.

Were both of the affected negs from the same holder?

Frank53 · Jan 29, 2022

I think you’re right. I just developed 4 more films,I shot on the sam morning. They are all ok.
Thanks for the input.

BrianShaw · Jan 29, 2022

Are those pics “natural light” or strobe illuminated? Did you use a lens hood?

Frank53 · Jan 29, 2022

It’s early morning natural light. Incident light metered near the front trees, to get a dark background.

Nitroplait · Jan 29, 2022

The reason seeing the whole negative is relevant, is that it allows us to see if normally unexposed edge areas are also affected by the leak - and important clue as to where and when in the process it happened.
I am puzzled by these leaks as they are almost identical, but the light obviously came from two different directions thus in-camera exposure is unlikely. The filmholder is a possible culprit but it could be in the loading process as well as during handling. I don't know your processing methodology, but that is also a possibility.

Frank53 · Jan 29, 2022

Nitroplait said:
The reason seeing the whole negative is relevant, is that it allows us to see if normally unexposed edge areas are also affected by the leak - and important clue as to where and when in the process it happened.
I am puzzled by these leaks as they are almost identical, but the light obviously came from two different directions thus in-camera exposure is unlikely. The filmholder is a possible culprit but it could be in the loading process as well as during handling. I don't know your processing methodology, but that is also a possibility.

The edges are not affected. Those two are from the same filmholder, so the light is coming from the same direction, as the holder is turned to expose the other film.
There still could have gone something wrong, loading the holders. I usually load twenty or more of them, to have them ready when I go out shooting, so I may get less accurate after some time
So I will check the holder I used and be even more careful loading them next time. I’m glad this new, to me, camera does not seem to be the cause.

Donald Qualls · Jan 29, 2022

BrianShaw said:
when pulling the dark slide that you inadvertently jiggled the holder from the back causing light hurt leak.

First, although they're from the same corner of the film holder (one upper and the other lower because, as you noted, the holder was inverted between exposures), they're from the left side of the camera. Assuming your camera back is mounted in the usual orientation (open to the user's right), that means these are on the flap end of the film holder. Same holder corner means it's not something under the ground glass panel (therefore hidden from easy view) blocking the holder up off the reference surface (that would also lead to defocus, worst in that corner and least at the dark slide end).

The only film holder fault I see that could cause this kind of light strike with the shadow (perhaps cast by the edge of the built-in film sheath) is a crack in a plastic holder that runs across the entire edge, letting light in under the dark slide when the holder is out of the camera. The internal sheath would shield the rebate, and cast the shadow we see. If the crack is small, it might have very little effect when the holder is in your bag, casting light only when direct light falls on the crack.

Bill Burk · Jan 29, 2022

I used to notice while pulling darkslide on a Grafmatic a corner would lift because the graflok was loose. After tightening it I never had the problem again. I also have a camera with a spring back that didn’t fit the Grafmatic. So I filed the end down to accept it. Kind of like what people do with Holga cameras and electrical tape, I created a felt/plastic cover for the tail end to protect the area I filed. (It’s an ugly New Vue so I wasn’t going for looks).

grat · Jan 29, 2022

Are you sure the film holder is seating correctly? I'd take the film holder, with no film, put it into the camera, remove the lens board, and look into the bellows while shining a bright light around the edges and corners of the film holder.

takilmaboxer · Feb 7, 2022

Another way is to load the film holder, take it outside on a sunny day, don't put it the camera, just move it around in space so light has a chance to strike it from all directions. Then develop the sheet, and if there are leaks like this, they are in the holder and not related to your in-camera technique. I have experienced only leaks at the hinge end of holders, caused by old tape. The holders I own can tolerate direct sunlight for brief periods, even the old wood ones.

Is it possible that a 4x5 film cassette is leaking light?

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