How to tell if a darkroom is film safe?

Discussion in 'Darkroom Equipment' started by wiseowl, Jun 21, 2004.

  1. wiseowl

    wiseowl Member

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    My darkroom has a few light leaks, mainly around the door. I've proven it's safe for paper by putting a coin on paper, leaving it for 15 mins and then developing the paper. Nothing new in that.

    I want to start loading my tanks in there, rather than using a changing bag. I know I need to improve my door seals (any suggestions welcomed BTW). However once I think I'm OK, how can I check it? Being a 35mm, roll film user doesn't seem to lend itself to the coin test, and would the coin test be valid for film anyway? So how does one check to see if a darkroom is film safe?

    Cheers

    Martin
     
  2. wdemere

    wdemere Member

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    From what I have read, the human eye is the best detector of light leaks. Just wait 10 minutes and then see if you can see. That seems to be all that is required.

    Best,

    William
     
  3. geraldatwork

    geraldatwork Member

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    My darkroom sounds a little like yours. It is in an expanded garage with running water. In daytime there are a few scattered leaks from windows and doors. When I enlarge in the daytime I hang some light blocking curtains which has worked well. If I enlarge at night I don't need the curtains as the slight leaks haven't been detrimental. When I load film in the small tank for developing I just make sure I do it at night and have never had a problem. Don't know if this helps just my experience. But the advice let your eyes be the judge is the best advice.
     
  4. jim kirk jr.

    jim kirk jr. Member

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    Once the door leaks are sealed have someone,friend or family member stand out side with a flashlight around anyplace that may leak light.like both Gerald and William have said,let your eyes be the judge.If your still not sure test a roll of film-from what I have done to check cameras for Ir leaks is to shot a roll with the cap on and see the results.
    It should work for rooms too.Hope I've helped.

    Jim
     
  5. Deniz

    Deniz Member

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    I have minor leakage too during bright days.. what i do is I flip an empty tray over the tray i have film in and develop like that.

    works for me.
    Some black fabric could work for you...

    peace
     
  6. mikewhi

    mikewhi Member

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    Don't forget the inverse square law of light, either. By the time the light travels from the bottom corner of a door all the way to your easel\trays\whatever, it has lost a LOT of intensity. Of course, there is no reason not to apply some weatherstripping where appropriate. But don't worry too much about those tiny little leaks.

    BTW, another source of leaks, and techies may want to jump in here, is flourescent bulbs in the darkroom. I had a friend who had them and when he shut turned them off, we sat in the dark for 5 minutes until our eyes adjusted and it sure looked like they were giving off a distinct glow. I know these things don't just shut off like a filament bulb, but anyone know the details on these in the darkroom? I had him remove them permanently just to be 'safe'.

    -Mike
     
  7. bjorke

    bjorke Member

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    The right way to know: test it

    Take some unexposed film, open it and let it hang out for about the time you expect it to be out when using film. Cover half of it and let the rest stay out for about as long again (2x total exposure). Process. Are the negs clear, or black?
     
  8. Ed Sukach

    Ed Sukach Member

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    One other idea: I've taken my Gossen Ultra-Pro meter, set it to the highest possible film speed (this thing goes to DIN 60 - ISO 800,000) and the largest possible aperture (f/0.7) and taken readings in my darkroom to determine exposure time. So far it has been out of range - more than eight (8) hours.
    Although my darkroom LOOKS leaky to my dark-accustomed eyes - I think I am reasonably safe.
     
  9. Ole

    Ole Moderator Staff Member Moderator

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    My darkroom is leaky enough that I develop films by inspection without a safelight. No fogging observed so far - even when I did a sheet in 45min stand development while I worked on something else.

    It's amazing how sensitive the eye is after a few minutes in near-total darkness.
     
  10. BWGirl

    BWGirl Member

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    Weather strip around the door frame (felt works really well), and a "draft dodger" on the floor against the door. (A draft dodger is a long tubular piece of fabric filled with batting, dried peas/beans or whatever.) A friend picked one up at a garage sale for about $.25US for me & it works great. I had been using a rolled up beach towel until the arrival of the dodger!

    I load my film in there no problem, now.
    Jeanette
     
  11. glbeas

    glbeas Member

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    I did the door seals in my darkroom with the metal and plastic things from Home Depot for sealing out drafts. The plastic bead on it presses against the door when closed and makes a perfect light seal. To install it I just shut the door, held the bar against the door frame with the seal in place on the door and pushed it a little for compression, then screwed it into place. The bottom of the door got a sweep, basically a bar with a flap that drags the floor and a metal threshold that the sweep seals against. That left a few leaks that were shut up with foam weatherstrip in the corners at the bottom. Works really well, looks good and I don't expect it to wear out any sooner than I will.
     
  12. photomc

    photomc Member

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    I also use weather stip, which worked well until a four legged friend thought is was fun to play with. Thinking about taking an old bed sheet folded and hanging over the door way. Right now, it is used at the bottom of the door and works very well.
     
  13. Loose Gravel

    Loose Gravel Member

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    I just did mine by painting the edge of the door black and using a V-shape plastic weather stripping. Still leaks a little, but I think there is more light coming off the timer than under the door. In my younger, cheaper days, I closed the door and rolled down a piece of black cloth. When all else fails, close your eyes.
     
  14. wiseowl

    wiseowl Member

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    Thanks for all the advice, given my doorway I think that it'll be weather strip, black paint and a draft dodger. If that fails then I'll have to rely on closing my eyes, thanks for that tip loose gravel, don't know why I didn't think of it before. :smile:

    Cheers

    Martin