Camera light leaks?

[Chrissy]

Hello! Please could I have your opinions on the weird dark marks on the edges of 2 rolls of Tri x 400 film I've just processed today, in Ilfotec HC 6.5 mins 20 °. I processed 3 rolls together, one was a TMax 400 shot on my trusty Nikkormat - and that looks normal - and fine...the other 2 rolls were Tri x 400 but shot on a newly acquired little Nikon FG20 I just bought as a back up camera. All 3 rolls in the same 3 roll Paterson tank at same time, so I'm ruling out a chemistry problem, which was fresh. These marks all appear in the same place on the Tri x films, the Tmax was in the middle of the tank, the Tri x's have the same pattern marks but also each has the same long strips of dark fogged looking marks, left side lighter than the black streaks on the right side...this seems like it must be a light leak in the camera? Maybe light leaking in the sprocket area or is it worse since the streaks look so long? Not affecting the actual images but reason enough to ditch the camera should it get worse? I can't think of anything else and am shooting a roll of the Tri x in my Nikkormat to see what that does to test the film 😕 (film always stored in the fridge too and not expired) thanks for any opinions! Cheers, Chrissy 

[stuart_pratt]

Odd. I wonder if your newly acquired FG20 had recently undergone a light seal change, and that person didn’t run the door seal strip right up to the seals in the door rails? It’s a very clean edge, normally light leaks might look a bit more diffuse than that, but that would be my guess. That might explain why you have it both sides of the film.

[rodeo_joe1]

3 hours ago, stuart_pratt said:

It’s a very clean edge, normally light leaks might look a bit more diffuse than that, but that would be my guess.

I agree. Far too sharply defined to be a back leak. But the grey streak on the other side of the film looks like under-fixing or a drying mark. And how would a light leak get a lighter 'halo' on one side? 

If the dark streak was only on one edge of one film, then I'd say insufficient fixer in the tank, but that wouldn't account for two films being affected. 

Wild guess: Is the FG20 fitted with a data-back? Because a faulty date imprint that's permanently on could account for the continuous dark streak. 

Give the camera a thorough inspection. Looking, as Stuart says, for lack of foam sealing in the back, or even pinholes! Although the FG20 has a labyrinth-type back seal that should be pretty light tight even with perished foam.

Give your changing-bag a once over as well. 

Other than that - there's the possibility of a manufacturing or pre-exposure fault with the film. We're the two affected rolls from the same batch or bulk loaded? 

Edited January 9, 2023 by rodeo_joe1

[Chrissy]

Thanks Stuart and Joe, really appreciate your comments and advice. So I looked closely at the camera light seals and found them to be crumbly in parts 😔 particularly right near where the sprockets are so this might be the cause. I think I know what you mean Stuart about door seals not running the entire length of the door, the foam just stops in the pics? And lastly, because I didn't like the slight pinkish tinge of the Tri X films (Tmax looks fine) I refixed (Hypam rapid) an extra 5 or so mins and the dark streaks have curiously faded to now lighter streaks. Pink tinge gone. But that is puzzling to me how the black streaks have now faded. (Am also guessing Tri X might generally require longer fixing times...) Any advice for replacing light seals, is this a careful DIY job or best left to an expert? 🙂 uploading pics of the seals and thanks for any tips in advance, Cheers, Chrissy 

[stuart_pratt]

I certainly won’t hurt to change the light seals, and it’s not a difficult job really. You should be able to find light seal foam on eBay. I can’t tell from your pictures if there is a hinge seal on the body side of the hinge, or if what appears to be the remains of foam there is an imprint of the foam left by the door hinge seal. I think it must be the latter since it would be odd to have seals on both sides. For the door rails, I cut a sheet of foam you can buy at a hobby suppliers with a wheel cutter to about 2mm thick and push it in with a cocktail stick, you could measure it, but I do it by eye.  It stays there by the fact that it is slightly compressed. The other seals will need to be self adhesive foam of the correct thickness. You’ll have to stab a guess at what that was, and choose the foam you feel is correct. Probably, the seals as they are now are half the thickness they were originally. If the door won’t close, you’ve gone too thick (and you might damage the hinge). Cover the film gate with a good stiff piece of card taped down before you start, as you don’t want the goo from the old seals in the mirror box or on the shutter anywhere. Take a photo of what you have before you start so you can replicate it, and then scrape off all the old foam. A very small amount of lighter fluid, and I mean small might help clean the actual glue off (often the foam comes off OK but leaves the residue of the old glue) but be careful. I put a few drops on a tiny rolled up piece of paper towel and run it into the door rails, leave it a while, and then scrape out. Make sure you run the door hinge seal right up to the edges so it meets the door rail foam so you remove the possibility of the marks you are getting. That might solve it, might not, but if you have gummy seals, you should replace them anyway.

The pink dye is the anti-halation dye in the film. It helps stop light bouncing around and fogging your film. If you wash longer, it should disappear. If you pour out the wash water in a white sink, you can usually tell when it’s gone. If you do the inversion method of washing, this will be well beyond the amount you need to rid the film of fixer in my experience. Good luck.

Edited January 10, 2023 by stuart_pratt
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[Chrissy]

Awesome, thanks so much Stuart for taking the time to advise in such a helpful, detailed way. Definitely seems doable now thanks to your comprehensive advice, will be checking out eBay, and get this camera fixed up! It seems otherwise in good shape and so lightweight (shockingly light when you've used Nikkormats all your life!) I took another picture of the seal around the body part and I think it's intact..? Great tip thanks for using a white tray to test for thorough washing; I try to go easy on water use being on rural tank water and am using hypo clear. Anyway cheers for all the help, its very much appreciated, 😀Chrissy 

[rodeo_joe1]

When I've replaced foam light seals, the worst part of the job was removing the old, gooey stuff. That needed a dozen or more cotton-buds (Q-tips) and some white spirit to clean out the light-trap channels. After that, inserting the new foam was a doddle. 

I managed to source some artificial rubber foam about 1mm thick and stuck a strip of double-sided tape to it. Then used a straightedge and craft knife to cut thin strips of the, now adhesive-backed, foam. It pushed into the channels of the camera easily with a blunted toothpick. 

The camera (a Mamiya 1000s) also had some wider foam pads at the door hinge. These I replaced with black nylon velvet material, since I never want to have to do the messy job of scraping gooey foam off the door ever again. 

I actually had 4 M645 cameras to do, and had nightmares involving black goo for a few nights afterwards! 😱

[stuart_pratt]

It doesn't look too bad, but test it with something pointed - if it's sticky, I'd change it.

Camera light seal foam and felt *BUMPER PACK* - Milly's Cameras (cameramill.co.uk)  if you are in the UK.

Edited January 10, 2023 by stuart_pratt
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[SCL]

YES - replace the light seals. I've done it for most of the used older cameras I've bought for the last 20 or so years. I was a little apprehensive initially, but quickly realized it was a pretty simple task, requiring mostly a little patience. I use a little naphtha (aka lighter fluid), Q-tips and toothpicks to clean all parts from gooey or dried seals, careful to not let the goo drop into spaces it wasn't intended to be. Then a final clean. The seal on the door I often use a strip of black ribbon material or black felt if the ribbon is too thin. Ideally I'd use foam along the top and bottom, but I've found that black  knitting yarn works just as well, although others abhore this approach. Once it is compressed several days, everything stays in place and does the job just fine. You can also find in many hobby shops sheets of black foam from 1-2.5mm thick, which is easily cut with a ruler and xacto knife for top and bottom seals. I don't know how wll this holds up over time though. In any case, the job is usually a quickie and well worth the effort. So good luck and hopefully it will solve your problem.

[AJG]

Tri-X should have a shorter fixing time than T-Max, other things being equal.

[John Seaman]

1 hour ago, SCL said:

I've found that black  knitting yarn works just as well, although others abhore this approach.

I've re-sealed perhaps 100 cameras with wool in the film door grooves, both for my own use and to sell, with no problems reported. Actually I don't even clean out the old foam out of the grooves, just scrape out any grit or bits of film. The wool is kept in place with silicone glue. The hinge seal and mirror bumper are replaced with sticky back black felt, after scraping off all the old stuff. But everyone has their own method which works for them.

[Chrissy]

Thanks everyone for your amazing help! Looks like ebay is my best bet, even foam is hard to get in this expensive little country, even black knitting yarn!!! Anyway cheers and thanks to you all for the encouragement ☺️

[Alan Marcus]

A tiny keychain flashlight inserted into the camera and turned on will light up the interior. Now go dark and examine the camera. Takes you 15 to 20 minutes to dark adapt. Sit in the dark with the camera and turned-on flashlight. Light tight? If yes, the light leaks out also. This works, you need to find a tiny flashlight that stays on.  

[Chrissy]

Thanks Alan, that's a brilliant idea to try out! I think I have a tiny flashlight somewhere...😀 Cheers!