Diagnosing light leak

Discussion in 'Modern Film Cameras' started by jeffgol, Nov 20, 2017.

  1. CED8ED92-5682-4347-96B7-3CF42891E812.jpeg Can anyone here give me an idea of what’s causing this light leak? Camera in Nikon F3,
  2. Do the leaks align with the sprocket holes?
  3. Yes they do but not every frame has streaks?
  4. Tony Parsons

    Tony Parsons Norfolk and Good

    Had something similar myself, when I had just started processing - caused by insufficient agitation, although I cannot recall if it was dev or fix. Possible here ?
  5. I did not develop myself had it done professionally
  6. Sandy Vongries

    Sandy Vongries Moderator Staff Member

    Use blue painters tape and go round the edges of the back - there really is no other place I can think of for light to leak on intact an F 3. "Pro" Labs make mistakes sometimes - it looks like it might be an agitation issue to me as well.
  7. Try another lab. The door hinge seal is usually the culprit but the streaks would be vertical across the frame and not centered on the sprocket holes.
  8. Sandy Vongries

    Sandy Vongries Moderator Staff Member

    When last I looked, the F3 hasn't got one.
  9. There's a seal on the hinge side (inside the back) but not on the lock side.
  10. Look again, bro.
  11. Do you know how the lab developed it?
    Basket line/tank/dip & dunk ot R/T processor.
  12. That looks like classic sprocket-hole "streamers" from bad processing to me. Made more visible if the film has been pushed and its contrast increased. Or a weak image has had its contrast increased in scanning.

    For those trails to be caused by light leaks would require light to be leaking equally top and bottom of the film back, and very evenly. Light leaks are usually far more random in appearance.

    Having said that, it wouldn't hurt to check the condition of the sealing material around the film-chamber. Any F3 is going to be old enough to maybe require service.

    Whatever the cause, the grain, and what looks like micro-dirt on that film is horrendous. I'd change labs just on that basis alone.
  13. Thanks for the reply’s, I just had another roll developed from the same camera and the negatives look ok(unable to scan them) as I’m not seeing those streaks by just looking at them. But the other roll that was shot with my F2 had about 15 frames in the middle of the roll come back unexposed(blank)? The frames on both ends look fine? Also I’m a newbie to this film thing so unsure about what you mean by the grain and micro dirt, the film was 400 iso pushes to 800
  14. By 'micro dirt' I mean fine particles of dust or other deposits stuck to the surface of the film during processing. It doesn't brush off and produces tiny white spots in the final image. It can come from overused developer, hard/unfiltered water, or just general poor cleanliness.

    'Grain' is what makes a black and white film image. It's the tiny particles of silver created from the emulsion when film is developed. Or at least they should be tiny. The grain in your example above is unacceptably large for a 400 ISO film IMO.

    You say it was 'pushed' to 800 ISO?
    You do realise that 'pushing' (i.e. extending development) actually does nothing to the film speed? The speed of a film is pretty much manufactured in, and can't really be changed. All that push processing does is increase contrast and grain. So if you need a faster film, then buy a faster film in the first place, but no film available has a true ISO rating much above 1200.

    WRT the F2 issue. Is the film completely transparent in the middle? Or are there some edge markings visible?
    Are the developed frames complete? Or are there parts of the fame missing?

    It's possible that this too might be a processing fault if the edge markings are absent.

    Of course, you could always save yourself grief by shooting digital. Using film is always going to add a layer of risk that's beyond your control. And you get no merit points in the eyes of the average viewer for shooting film.
    Last edited: Nov 22, 2017
  15. Thanks for the insight much appreciated, as far as the roll from the F2 there are numbers showing on all frames and the first 4 frames look good then the next 3 are half foggy, after that there’s a chunk in the middle that are transparent and the last 6 look good. Again I have not scanned these yet as I’m in the process of buying a scanner, thanks.
  16. Classic result of degraded door channel seals - check and replace.
  17. Dustin McAmera

    Dustin McAmera Yorkshire, mostly on film.

    But why would a leak show as regular streaks? To me that looks like 'surge marks' from the developer. I got a similar effect one time, when I was trying out a 1940's Agfa film. Only, my frames showed one pale streak per perforation; yours seems to have two. I was advised (on Flickr) that I was probably agitating the tank too violently. I can't pretend that I understand completely what's supposed to go on. The guy argued that fresh developer 'squirts' through the perforations, so the adjacent area gets too much development. Anyhow, I tried to be more gentle, and the problem went away.

    Here's an example of mine:
  18. "Classic result of degraded door channel seals - check and replace."

    - I disagree. Light leaking top and bottom of the camera back in equal measure seems unlikely. And it wouldn't give a double streak to every sprocket hole.

    Fogging through the layered sprockets on the take-up spool seems more likely. This could be caused by the back being momentarily opened, or a leak at the take-up end of the back. However, I'm still not convinced it's a light leak at all.

    Another cause could be handling the spool out of its cassette in a less-than-perfect darkroom. Given the apparently amateurish processing, I wouldn't rule that out either.
  19. "But why would a leak show as regular streaks? To me that looks like 'surge marks' from the developer."
    That was why I was asking about the exact developing method. Bromide Drag (the correct term) is caused by under agitating, but id it was processed in any of the 3 main types of film processor the streak would be along, not across the film. Reel & basket or tank & reel would cause bromide drag across the film, but the effect would be the opposite, dark (printed) steaks. The fim under develops locally as bromides "smear" acting as a developing agent inhibitor.
    I'd look at the little foam door seals first. Maybe try a strip of black electrical tape around the seam & see if that cures the problem.
  20. Chaz, I doubt that any 'professional' lab these days runs a continuous feed B&W line. Demand is too low. Nobody's going to keep gallons of dev and fix hanging around in a dip 'n' dunk or roller processor just "on the off chance" of a B&W order.

    It's going to be done as a small batch in a 3 gallon tank using reels and basket, or even an individual inversion tank job.

    There are also two types of streamer. 1) As you described, caused by a local build up of oxidised developer and bromide. 2) Caused by excessive agitation creating turbulence and local overdevelopment.
    The latter is more common with 35mm film as developer surges through the sprocket holes with excessive agitation. Plus the lack of any developable material in the sprocket holes creates pockets of fresh developer.

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