Opening the camera's back before unwinding

Discussion in 'Black and White' started by stephanie_vazquez, Apr 12, 2016.

  1. Hello. I've only been doing photography with a film camera for a couple of months now, and I know that exposing unprocessed film to the light will damage the images. However, I once opened the back of the camera for a few seconds by accident and the film was completely fine. I'm using TRI-X 400 film if that matters, but does anyone know why the film was fine and if the short time it was exposed played a role?
     
  2. Presumably the camera back was open for too short a time in too little ambient light. Just luck.
     
  3. 35mm film comes in a magazine/cartridge/cassette that is light tight to protect the film inside. If you have just loaded a camera and not started taking pictures yet, only the first few inches of the roll are outside the magazine and therefore exposed to light. If that's what happened, the rest of the roll should have been fine because the film was still inside the magazine.

    If you have started taking pictures and are in the middle of a roll, again the amount of film still inside the magazine will be fine. Of the pictures you have already shot, if the film is wound up tightly on the takeup spool as it should be, the outer layer or two can be enough to protect the inner layers wound around the spool, but you would lose few inches that are directly exposed to light. And if you are at the very end of the roll, you might lose the last few inches but most of the roll could be protected by the last layer or two of film wrapped around the earlier part of the roll.

    Same general idea is true with paper-backed roll film, but the 35mm magazine provides better protection on the supply end and the roll film paper backing provides better protection on the takeup end.

    Keep in mind that light travels at 186,000 miles per second. Any openng of the camera back, no matter how brief, will expose film that is laying there open to the light (not still inside the magazine or wound up on the takeup spool). And almost any level of light short of being in a darkroom or inside a changing bag is enough light.

    "I once opened the back of the camera for a few seconds by accident and the film was completely fine"

    To say that the film was "completely" fine is difficult to account for. To say that the parts you care about were fine would be different.
     
  4. Craig pretty much said it.
    If you released the latch, but didn't actually open the back, there might not be any light in.
    Films with a RemJet backing are pretty well protected against light from the back. Professional movie cameras load large, maybe 1000 foot, rolls such that the film itself keeps the light from the rest of the roll. Normal film isn't quite that opaque, but does keep much of the light out.
    Home movie film before Super-8 also worked that way.
    Also, I once had a roll of Russian 35mm film that was wrapped with foil around the spool of film, with no metal cartridge. Load it in dim light, and keep the film tight on the spool, and it works.
     
  5. Luck probably, I had that happen to me while I was on mid roll and still only a few frames got ruined.
     
  6. Thank you for the responses and it is true that the strip that was exposed to the light was slightly different, yet the images were not ruined. What surprised me was the condition of the rest of the film, which was fine compared to what I feared would happen.
     
  7. Which film is it? And 35mm, 120, or something else?
     
  8. Glen H, I'm using Kodak Tri-x400 135-36 36mm film.
     
  9. I was'nt that lucky, developed Agfa Copex Rapid film which has no backing in a Paterson tank
    without the light guard tube. Half of the film is blacked out, only 50% image rescued.
     
  10. Film is opaque when you are taking pictures, so if you open the back before rewinding the film and after taking 36 shots you lose a couple of exposures but the light never reaches the majority of the film. I've done it a few times and only ever lost a few shots.
     
  11. Most film isn't quite opaque enough to keep itself from being exposed, but it protects underlying layers fairly well.
    It depends on things like the specific antihalation used, for one, or rem-jet which does protect pretty well.
    I wouldn't guess that Tri-X backing was enough to protect the frame ready to expose, but maybe.
     

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