Pinhole light leak

Discussion in 'Pinhole Photography' started by dustym, Aug 19, 2006.

  1. dustym

    dustym Member

    Messages:
    165
    Joined:
    Oct 16, 2005
    Location:
    Essex, just
    Shooter:
    Multi Format
    From top of neg to bottom in a arrow head shape the apex of the leak in top slap bang in the middle of the top edge and then flares out to the bottom edge 5x4 negative.
    Is this likely to be a leak from the pinhole rather than the back. The d/slide held in place via 2 tensioners d/slide exposed side sealed by black felt.

    rgds
     
  2. Donald Miller

    Donald Miller Member

    Messages:
    6,242
    Joined:
    Dec 21, 2002
    Shooter:
    Large Format
    Why don't you find out difinitively rather than considering a bunch of guesses? The way to do this is to remove the lens board and while in a dark room insert a light through the lens board opening and shine it around inside the camera bellows with a holder in place in the back. The light leak will show up.
     
  3. dustym

    dustym Member

    Messages:
    165
    Joined:
    Oct 16, 2005
    Location:
    Essex, just
    Shooter:
    Multi Format
    Its a wooden box pinhole

    .

    The lens board is static, I supopose I could shine a light through pinhole but this would not give the integrity of the seal around the darkslide.but it will tell me if there is a leak around the pinhole mount.

    Thanks Donald
     
  4. blokeman

    blokeman Member

    Messages:
    140
    Joined:
    Jan 3, 2006
    Location:
    Melbourne
    Shooter:
    Multi Format
    Try covering the darkslide with cloth when making the exposure, if it still shows flares after that then I suggest it could be flaring off the actual pin-hole especially if it is made of tinfoil/aluminium or such. But, sometimes these can be capitalised on!
     
  5. dustym

    dustym Member

    Messages:
    165
    Joined:
    Oct 16, 2005
    Location:
    Essex, just
    Shooter:
    Multi Format
    The pinhole is bare metal aluminium , should I try darkening it
     
  6. Jim Jones

    Jim Jones Subscriber

    Messages:
    2,463
    Joined:
    Jan 16, 2006
    Location:
    Rural NW MO
    Shooter:
    Multi Format
    Yes! Even a small felt tip pen will darken it better than nothing. Check for residue after darkening it. Since good pinholes are easy to make, you might consider making one out of brass shim stock, usually available at hardware or hobby shops. It works cleaner than aluminium. Also, a "lens hood" sometimes eliminates stray light.
     
  7. blokeman

    blokeman Member

    Messages:
    140
    Joined:
    Jan 3, 2006
    Location:
    Melbourne
    Shooter:
    Multi Format
    From my experience the flare is moderated by the thickness of the aluminium. One way to avoid it can be to make the hole and around it a darker colour, texta pen could do this. Also, make sure every surface inside the camera is black, preferably matt-black. I'm not sure if you know but there is a pinhole website online, I'm not sure of the technical content but it's called f295 and similar in set-out to APUG. I've used handmade exposure apparatus for years, p.m. me if you need some more info. I wouldn't call myself a technical expert but I have years of experience. Good luck.