Please help me figure out this light leak. I'm loosing my mind!

grat · Sep 16, 2022

Donald Qualls said:
But those wouldn't fog under the film guides; those are usually metal and would provide excellent shielding from the alpha and beta emissions of a thoriated lens element (and any gamma from these is so weak as not to matter unless you leave the lens sitting right on the film with the dark slide out).

Understood. I was largely being facetious anyway-- if the lenses could fog film, they'd be useless on cameras with cloth shutters. It's an odd light leak, though.

jnk · Sep 17, 2022

cirwin2010 said:
I always remove my watch before doing any sort of darkroom related work so I don't risk fogging anything. It also would catch on the film changing bag if I didn't.

no darkroom timers clocks or glow in the dark tape ? have you ever just stood or sat there for 5 minutes so your eyes get adjusted and looked for light in the dark? it can leek into darkness and you don't see it until you notice it. your problem looks like your film saw light before or after it went into your double dark slides. was it you who broke the box-seal of your film or it was not factory sealed? maybe these problems are not yours but owned by someone else who previously owned your film

xya · Sep 18, 2022

Sirius Glass said:
I too remove my watch which does not have any glowing parts but I do not want to have it catch on the sleeves of the changing bag or anything else.

So do I. The sleeve fits better without watch.

Europan · Sep 19, 2022

When I started commercial processing at my black-and-white lab in 1999 I soon got in contact with a photographer who was into architecture. He told me that he got streaks on 120 negatives and the edges never clean. I proposed to develop a roll parallel to him developing an other, equal exposures on both. He was stunned by what I delivered which was only possible through constant agitation of the spiral reel in a large open trough. The films, by the way, were Fuji Acros and the price he payed me was 12 Swiss Francs. For that success I was happy to have stood in the dark with rubber gloves on.

Doremus Scudder · Sep 19, 2022

Bill Burk said:
Ah but the rebates would be clear if darkslide wasn’t opaque

Yes, indeed! I overlooked that detail... The film must be getting light struck out of the holder somewhere. Light leaks in the darkroom are often hard to find. I had one that fogged film in the developer tray - really puzzling till I placed a mirror in the bottom of the tray and found a small pinhole in my window covering that the film could see, but I couldn't.

Donald Qualls · Sep 20, 2022

Doremus Scudder said:
Light leaks in the darkroom are often hard to find.

Yes indeed. Was the batch with fogged rebates done in daytime, but the tests at night? Or fogged on a bright day and not fogged during a storm?

Mind you, my last couple darkrooms have had a light level where, after a half hour in the dark, I could faintly see my hand against the door or window cover (i.e. light coming through the wood) but didn't fog the film, even fast film.

winger · Sep 21, 2022

When you're out shooting and remove the darkslide, do you block the opening while the darkslide is out? If the leaks only happen when the sun is coming from the side of the opening, maybe it's that?

Fluidphoto · Sep 22, 2022

Try running a strip of electrical tape along the hinge of the holder after you load it and then shoot as you normally would. I have a bunch of older wooden holders that had bad hinges and used to leak at the corners. Hockey tape has worked wonders and is still going strong after 20+ years but it's hard to remove after a test.

Donald Qualls · Sep 22, 2022

Fluidphoto said:
Try running a strip of electrical tape along the hinge of the holder after you load it and then shoot as you normally would. I have a bunch of older wooden holders that had bad hinges and used to leak at the corners. Hockey tape has worked wonders and is still going strong after 20+ years but it's hard to remove after a test.

The original hinge tape is cloth-reinforced gaffer tape. Not too hard to come by, though the old is likely to be annoying to get off. Lighter fluid (naphtha) works pretty well to soften the ancient adhesive and won't hurt either wood or the plastic used to mold film holders.

tomatojoe · Sep 22, 2022

Fluidphoto said:
Try running a strip of electrical tape along the hinge of the holder after you load it and then shoot as you normally would. I have a bunch of older wooden holders that had bad hinges and used to leak at the corners. Hockey tape has worked wonders and is still going strong after 20+ years but it's hard to remove after a test.

book binder book repair tape is good to use too

Please help me figure out this light leak. I'm loosing my mind!

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