Any thoughts on this shooting/processing fault?

[Peter B]

With all the recent chat about Bronicas, I was moved to dig out the SQ-Am I haven't used in years and run a test film through it. A 2012 HP5+ meant a reasonable chance of hand-holding, and this was developed in HC-110 Dil B for the required 5 mins. Frames 3 and 9 displayed a definite pale strip fault which wasn't present on adjoining frames, and the camera was in a closed bag while not being used.

I stuck with the 50mm lens for all shots, so there was no chance of a problem there. Frame 3 is below and shows the pale fault to the right side against a darker subject, whereas in frame 9 it's mostly pale sky and harder to see. It's particularly noticeable that it doesn't cover the whole depth of the frame, so I'm a bit puzzled. The Bronica rolls the film from the top down to the take-up spool below if that helps with orientation?

 

[john.margetts]

That is clearly a light leak. There are several places that it could occur. There is a light seal around the angled baffle behind the mirror, another around the joint between the camera body and film back, the slot where the dark slide fits, the joint in the film back around the hinged cover.

If the leak is very small, it will only show up when the film is left without winding on for a while rather than in every shot.

As the mark is at the top of the image, the actual defect must be at the bottom of the camera - my best guess is the join between body and film back, at the bottom and towards the left.

 

[Karl.t1965]

Was the back stored with the dark slide fitted? If so the seal is probably gone

 

[Peter B]

That is clearly a light leak. There are several places that it could occur. There is a light seal around the angled baffle behind the mirror, another around the joint between the camera body and film back, the slot where the dark slide fits, the joint in the film back around the hinged cover.

If the leak is very small, it will only show up when the film is left without winding on for a while rather than in every shot.

As the mark is at the top of the image, the actual defect must be at the bottom of the camera - my best guess is the join between body and film back, at the bottom and towards the left.

Thanks John. The back I used is actually my best back, and it seems to have decent seals. Apologies for the bad phone shot, but the seals look OK and the back mating surface with the camera doesn't have seals. I'll check out the mirror seal later.

Was the back stored with the dark slide fitted? If so the seal is probably gone

Thanks Karl. The film was loaded and shot the same day, the first walk being about an hour and the second one less. The dark slide was fitted between each shot and the kit was in a zipped bag except when taking the photos.

 

[john.margetts]

Fitting the dark slide might be a problem. It is really intended for when you want to remove a back with a part used film.

 

[Peter B]

Fitting the dark slide might be a problem. It is really intended for when you want to remove a back with a part used film.

Ironically, I fitted it between shots just in case of any light leaks in the camera itself! I've had a quick look at the mirror seal as you suggested, and that's an awkward one. If anything, it looks like the seals at the side are dodgy, but not the end. More investigation required and perhaps the sacrifice of one of my really old films when the sun comes back out.