Bronica SQA light leaks + splotches. What's causing them?

[Pandysloo]

I just got my second roll back shot with my Bronica SQ-A. The first roll was completely free of light leaks, but the second one was full of them. For the first roll I shoot entirely on a tripod, and advanced to the next frame before reinserting the dark slide. For the second roll, I shot entirely handheld (except for 1 tripod shot). Because I was fumbling with the camera, I inserted the dark slide before advancing the crank with each shot, and the one tripod shot where I wound the film before inserting the slide is the one shot on the roll without a light leak. Could my sloppy darkslide handling have caused the leak? Is there a way to test for leaks without burning through film? Also, is there any reason to use a dark slide if I'm not changing out backs?



I also noticed black splotches on some of the frames. Does anyone know what this could possibly be?

[lxdude]

There is no need to use a dark slide if you are not changing out backs in mid-roll. You can use it to keep dust out of a loaded back off the camera before or after the roll is shot. Inserting/removing the dark slide should not cause a leak, but it can if the light seal is worn or damaged. Bronica recommends not carrying the camera with the dark slide in place because it defeats the interlock and the back can come off if the release button is accidentally depressed. Contact Jon Goodman (who is here on APUG) for one of his excellent light seal kits. In the meantime, don't use the dark slide and tape over the dark slide slot for extra security. You can change film by removing just the the insert to reload.

As to the blotches, clean the insert thoroughly with a alcohol on a Q-tip or light cloth like a microfiber cloth, and make sure to blow out any fibers afterward. That might help.

[Pandysloo]

Thanks that is helpful, but I'm not entirely clear. Are these leaks something that only occur in the dark slide slot, or do they occur on any crack on the film back? Would it be safe to assume its coming from the felt darkslide slot, or would I need to test it somehow to find the source? Sorry I'm new at this.

[lxdude]

The dark slide slot is the usual culprit. The other surfaces on the back and insert fit together without seals, so unless there is damage to the back or insert, the designed-in baffles will keep out light. Actually there are seals in the slots on the insert where the door on the back closes over the insert, but due to the depth of the slots light won't get past even if the seals are missing.

And welcome to APUG!

[Pandysloo]

So I opened it up and gave it an inspection. The black splotches were caused by the deteriorating seal at the top of the film back next to the ISO dial on top (is that what you were referring to as a seal that isn't neccessary?). It is pilly and covered in ink for some reason. I found ink splotches on the main rollers as well as the little silver rollers which I didn't even know existed until now. I didn't have any cotton swaps or alcohol, so I used warm water and a paper towel instead.

Could the leak be caused by this deteriorating seal? The light leaks were horizontal, so I don't see how it could be the cause. Took off the film back, took out the dark slide, and tried to shine a light through the dark slide slot in a dark room and I couldn't find any leaks, though I did find more foam pills in the slot clogging it up.

Is the seal kit from Mr. Goodman for this foam specifically, or is there another seal I'm overlooking?

[Usagi]

Hi,

I had similar light leak in one of my SQ-Ai backs. The cause was same seal.

I bought foam from http://www.aki-asahi.com/store/ and fixed leak.

There's was one good tutorial in the net, but I can't find it any more.

[Dave in Kansas]

I've had light leaks just like yours on my SQ-A. Your foam seals are bad and need to be replaced. You can get light leaks through the dark slide opening if those seals are bad too. On some backs, the plastic plate that mates with the body can crack, usually at the corners near the small screws.

Dave

[Daire Quinlan]

I had almost exactly those same light leaks, in exactly the same location. Seals around the latch I suspect were the culprit. They weren't decayed but they were squashed and worn looking. Replaced them all with some self-adhesive foam I also got from aki-asahi and the problem has disappeared.

[Pandysloo]

Thanks for you help everyone! I ordered a repair kit from aki-asahi. I will report back if I run into any more problems.

[lxdude]

So I opened it up and gave it an inspection. The black splotches were caused by the deteriorating seal at the top of the film back next to the ISO dial on top (is that what you were referring to as a seal that isn't neccessary?). It is pilly and covered in ink for some reason. I found ink splotches on the main rollers as well as the little silver rollers which I didn't even know existed until now. I didn't have any cotton swaps or alcohol, so I used warm water and a paper towel instead.

Could the leak be caused by this deteriorating seal? The light leaks were horizontal, so I don't see how it could be the cause. Took off the film back, took out the dark slide, and tried to shine a light through the dark slide slot in a dark room and I couldn't find any leaks, though I did find more foam pills in the slot clogging it up.

Is the seal kit from Mr. Goodman for this foam specifically, or is there another seal I'm overlooking?

OOOPS!
I really shouldn't try to give others advice after a long and boisterous Halloween night.
Especially going from memory, as I don't have a film back handy.

I think that seal is necessary, though light leaks are still unlikely IMO without it. I don't think that's the cause of the leak-it looks to me like the dark slide slot is the cause of the streaks. The other seals I was talking about are inside the grooves on the back of the insert where the edges of the rear (hinged) half of the film back close over it. There is also a necessary seal made of felt on the bottom of the film back next to the hinge, which lasts longer than foam.

That deteriorated seal is foam, which has broken down from age. It causes that inky, sticky mess that I should have recognized as being from the seal, having dealt with it numerous times myself. It was widely used by manufacturers. Jon Goodman's kit contains a wooden tool to scrape it out, and then you need a little lighter fluid (naptha) and a lintless cloth to get it all off. Alcohol works, but I like lighter fluid. Using either on the rollers will ensure you got it all. I guess a paper towel would work as a cloth; just check for fibers afterward. Jon's kit cost me I think $10 a few years ago, and it contains all the seals needed for one back, and instructions. His kits are very high quality.

I have not used the kit from Aki-Asahi, but they have a good reputation for their camera leatherette replacement kits.