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TonyMiller
31st January 2011, 02:11 PM
I bought some 5x7 film holders from the auction site and most seem ok - except one. On both sides of the DDS the same light leak is apparent on the negative (see below - left hand side and slightly along the bottom). I have used the other holders in the 5x7 back with success so can only guess it's the holder. I can see some light through the taped hinged but that's not unusual from what I've read.
I can't see where the leak is coming from - or at least there's nothing apparent.
Anyone have any comments, ideas or suggestions how to pin it down and how to fix it if possible?
Thanks

http://www.millerstudios.co.uk/leak.jpg

Alan Clark
31st January 2011, 06:08 PM
Tony,
I'm clutching at straws here, but you could try sticking some light -tight tape to the hinged end of the darkslide. Don't overlap it onto the sides or you could upset the focus distance.
Black electricians tape may do, or even thin black light -tight fabric.

Alan

TonyMiller
31st January 2011, 06:35 PM
Thanks Alan.
I posted the picture to see if anyone had seen anything similar - long-shot I know!
I'm going through a process of elimination now. I have each DDS loaded with RC paper and exposing the closed holder to light to confirm which are ok or not. I can at least then count out the 5x7 back and concentrate on the offending holder.
Thanks again for your suggestion which I'll bear in mind when I'm done testing.

Alan Clark
31st January 2011, 07:12 PM
Another thought Tony; does the camera back have an "end stop" that the hinged end of the film holder butts up against? I made a 5 x 4 camera once that didn't, and got light leaks when the film was being exposed. After modifying the back by adding a strip of wood for the hinged end of the film holder to butt up against, no more light leaked in. Just a thought....

Alan

TonyMiller
31st January 2011, 07:58 PM
The camera back does have an end stop. I had the lens board off and looked through the front to the back with the holder in place and couldn't see any light though it may be too small to see that way.
Thanks

DaveP
31st January 2011, 08:33 PM
I've never had anything like this with 4x5 holders. Could it be possible that the darkslides on the larger 5x7 holders can bow a bit and give you light leaks? Might explain why the density of the leak is greater in the middle. And that bow might have pulled it away from the track at the bottom? Just thinking out loud.

cliveh
31st January 2011, 08:36 PM
Dispose of that DDS.

TonyMiller
31st January 2011, 08:48 PM
Interesting point Dave - just checked the holders and they all have a bit of give in them, this particular one no more than the others so I'm not sure. Frustrating - maybe Clive's succinct advice is the best! :)

I've never had anything like this with 4x5 holders. Could it be possible that the darkslides on the larger 5x7 holders can bow a bit and give you light leaks? Might explain why the density of the leak is greater in the middle. And that bow might have pulled it away from the track at the bottom? Just thinking out loud.

Michael
31st January 2011, 09:30 PM
The shape of that leak matches the typical shape of the end of a dark slide. I suspect the holder's lightproofing has become worn.

Barry
1st February 2011, 11:17 AM
I would try an exposure with a dark cloth over the darkslide end whilst removing/replacing and making an exposure to test the light trap with the darkslide removed.

TonyMiller
1st February 2011, 06:41 PM
Good advice Barry - I have read about using the dark cloth this way but never do it to my cost I think...:(
Thanks

TonyMiller
3rd February 2011, 02:18 PM
:o:o:o:o :slap:

Ok - thanks everyone for suggestions, ideas and help.
Unfortunately the cause of the light leak was a sausage-fingered Yorkshireman who shall remain nameless - ahem!
I took Barry's advice about covering the back of the camera (I know it's so obvious when you're told) and a bit of care when inserting and removing the darkslide and I'm pleased to say all the holders are light-tight. I think I was lifting slightly the other end of the holder when inserting the slide causing there to be a slight entry of light.
Thanks again!

Dave miller
3rd February 2011, 02:44 PM
:o:o:o:o :slap:

Ok - thanks everyone for suggestions, ideas and help.
Unfortunately the cause of the light leak was a sausage-fingered Yorkshireman who shall remain nameless - ahem!
I took Barry's advice about covering the back of the camera (I know it's so obvious when you're told) and a bit of care when inserting and removing the darkslide and I'm pleased to say all the holders are light-tight. I think I was lifting slightly the other end of the holder when inserting the slide causing there to be a slight entry of light.
Thanks again!

Good to read of a happy outcome, even if you are slightly pink. :)