Bronica SQAi film back light leak?

[Andy K]

Developed and printed a couple of rolls from my Bronica last night. It appears one of my film backs may be leaking light.

Here are a couple of examples from last night's enlarging session. As you can see, they are markedly lighter at the sides. This suggests the light is entering at the point the back mounts to the camera body... but then I'd expect lines across the negs too... so it could be getting in around the film loading 'door'?

Any ideas on how to solve this?

 

[Tom Kershaw]

Andy,

Could you post a scan showing the strip of film in question?

Tom.

 

[Andy K]

Tom, I can't scan film. In the attachment showing the pub you can see the print shows a 'lightening' towards the sides. This leads me to think light is getting in around the film loading door of the film back. I was wondering if one of john Goodman's kits would solve the issue.

 

[archphoto]

If you don't have the propper scanner: make a contact-print of the neg's involved and make a scan of the contact-print.
This could be a development issue too.

If the seals of your back feel sticky replace them with the ones from John Goodman.

Peter

 

[rmolson]

Light leaks in SQ backs

I have suffered through finding leaks in my SQ backs Replacing the seals is easier said than done if you are manually challenged. Try a process of elimination first,
Sometimes light leaks originate from sources other than the magazine.
Tape off the dark slide opening with black electricians tape .and see if it makes any difference. Replacing the seal on the dark slide opening is tricky .If you still get it, tape off the sides ,top and bottom of the magazine as soon as you load it and before you advance to the first frame. To eliminate any out side source cause the fog..
It took me three months before I discovered the focusing sheet on my enlarging easel was storing uv from my over head fluorescents and I was opening the mag on top of it.Simple answer once you find the cause

 

[DWThomas]

That's not the characteristic pattern of the leak I have experienced, but I've not wrestled with any dark slide issues -- yet. The problem I had was far from subtle. I have shots on PBase at the bottom of this page that shows the effect of almost no seal at all in the back opening, as well as shots of a working back showing locations and approximate dimensions of the back seals. The shots are of a working back I purchased used and the seals were not put in by me. But following what's seen in those views with some Jon Goodman kit material fixed my problem back.

The back-to-camera body interface has a groove and rib labyrinth sort of seal -- I'd think the attachment of the back would have to be really noticeably loose for light to get in that way (but some day I'll probably learn I'm wrong!)

DaveT

 

[Marcus S]

Andy, would it be possible that the roll was not wound up tight enough and light entered from the side?
It happend to me at one time and to prevent any light issues, I now place my exposed rolls in a light tight container and never take the film out until it goes into the darkroom.
I did have a light leak with one of my Bronica film backs. The light reached further into the middle of the negatives than shown on your photographs.

Marcus