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alex · Joined: 09 Oct 2002 Posts: 6 Location: Seattle

A light leak has begun to show up on most of my negatives. It doesn't matter which holder I use, so the problem doesn't seem to lie there. The leak always appears in the same place: if you are looking at the neg. with film notch in upper right corner, the leak begins on the lower right side, moving from right to left until it gradually fades out. What strikes me as unusual about it is that it has straight edges and at its beginning has a squared-off edge. I've tried shining a light down into the bellows in a dark room to check for leaks, but can't see any problems there.

Could it be that light is getting in between the spring back and the holder, and how could I test for this? And how could it be fixed?
Any advice from the august forum warmly welcomed.

Mickey · Joined: 04 Oct 2002 Posts: 11 Location: Columbus, OH

Just a suggestion but I'd try this: Put a film back in the camera remove the lens board in the front, shut off all lights, extend the bellows all the way out and put a flash light inside the bellows. You should be able to see any light leaks.

Les · Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI

Any advice from the august forum warmly welcomed.

Yeah we usually run about two months behind..

I think your theory is right. From what you say this streak is starting at the darkslide end of the film holder. You've got two possiblilites. The ridge on the holder is not seating perfectly with the goove in the camera. Maybe due to somethin in the groove.

Fiddle with a film holder in the camera and see if you can find out if it's hanging in the wrong place or not fully seated.

Do alex's light bulb test with a 25 watt bulb on an extension cord and have a film holder inplace when you do it.

alex · Joined: 09 Oct 2002 Posts: 6 Location: Seattle

Thanks to both Mickey and Les - I'll try the test with holder in and inspect the groove.

alex · Joined: 09 Oct 2002 Posts: 6 Location: Seattle

I've tried the tests suggested (putting the flashlight down into the bellows) but can find no light leaking out anywhere. Holders both old (wooden) and new (plastic) sit perfectly tightly and snugly in the spring back, and no light leaks out from them when I do the flashlight test.

To correct something said in someone's message: the light leak does not appear on the side nearest to the dark slide, but at the opposite end, nearest to the upper left hand corner if you are looking at the camera from the back.

I'm at my wits' end with this one and hope someone can think of a further troubleshooting test.

Les · Joined: 09 May 2001 Posts: 2682 Location: Detroit, MI

"To correct something said in someone's message: the light leak does not appear on the side nearest to the dark slide, but at the opposite end, nearest to the upper left hand corner if you are looking at the camera from the back. "

I don't mean to berate the matter but how is the ground glass oriented?

If the glass is horizontal and you put the film holder in from the right and the light leak is in the upper left, then it would be on top of the notches. But you said it begins at the lower right side--opposite the notches, which makes it the darkslide end of the holder.

If the glass is vertical and the leak is the upper left, then that's consistant with your first post, but will be a darkslide side leak.

I'm confused.

Oh and what camera are we talking about? Speed/crown, Linhof, Sinar, Gandolfi???

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alex · Joined: 09 Oct 2002 Posts: 6 Location: Seattle

It's confusing and an exercise in 3-D thinking, but I think I'm being consistent. What I mean is this: if you hold up a processed negative with the emulsion side facing away from you, the notch will be on the upper right corner and the trail caused by the light leak will appear on the bottom right corner. If you're thinking of the film loaded into a holder which is then inserted into the camera, the notched end will be on the lower left hand side and the light leak will be nearer the upper left corner - that is, if you are standing behind the camera with its back in vertical position.

The camera is a wooden-bodied Speed Graphic with side-mounted Hugo Meyer rangefinder.

45PSS · Posted: Thu Oct 24, 2002 1:37 am Post subject:

It's your darkslide seal(s) that are causing the problem. I'm betting you purchased the film holders close to the same time, they're the same age, and....."You Always put the darkslide in the same way."

Charles.

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The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.

clnfrd · Posted: Thu Oct 24, 2002 12:24 pm Post subject:

I don't think your holders, wood and plastic, all went bad in the same place at the same time. I've had the same problem occasionally with my miniature speed. On my speed there is a half-moon cut-out upper and lower, on the back of the camera body at the left end of where the film holder seats. Don't know the purpose of the cut-outs, but if the spring on the ground glass back isn't really strong, the film can get fogged, casting that square-edged shadow as the light leaks across the edges of the cut-out on the film holder with the dark slide removed. I would remove the back...find a way to hold the camera stationary...go into a dark room and stay until your eyes get accustomed to the dark...and with the lens board removed and a cloth over the front of the camera and light source so the light doesn't spoil your night vision...hold a film holder (one that has exhibited the fogging) very tightly in position on the back of the camera...and turn on the light source (probably a flashlight) and direct it through the opening where you removed the lens board toward the upper left of the camera back. You should see the leak. Also, the flat black paint gets worn off the back of the camera from the sliding in and out of the holders and this can allow light to be reflected to the film. Light rays cannot bend...they have to be REFLECTED around corners. Repeating, if the springs on your back aren't holding the holders really tight, you can get fogging. Another contributing factor is holders that aren't perfectly smooth at the joints where the end of the holder folds out for film loading. This prevents the holder from fitting extremely tight against the camera back. I have sanded some holders at these joints, or seams, and touched up with flat black paint. And, you probably already do this, but I wait 'til the last instant to pull the dark slide before making the exposure and then replace it immediately. Fred. P.S. ALSO, when the dark slide is out, even a slight bump on the film holder can cause it to rock and cause fogging on the left side..and, the simple act of pulling the dark slide if not done straight out with finesse can disturb the seating of the holder on the left side if the back has weak springs.

[ This Message was edited by: clnfrd on 2002-10-24 08:32 ]

[ This Message was edited by: clnfrd on 2002-10-24 09:14 ]

alex · Joined: 09 Oct 2002 Posts: 6 Location: Seattle

Thanks, Fred - this helps a lot and may well be the problem, though the springs certainly feel strong enough. If it is in fact a weak spring, what do you recommend? Buying a replacement back for the camera (I've seen them on Ebay)? Can one only fit another old spring back on, or could one put a Graflok back on? And what sort of money would this cost? Sorry for the barrage of questions!

clnfrd · Posted: Thu Oct 24, 2002 9:27 pm Post subject:

Alex, I have two spring backs for my 2X3 Speed, and the springs are a little sloppy on both. Acquiring another one may produce the same result. It may be possible to remove the springs and warp them in the opposite direction, within reason, to increase the tension. This method corrects the problem for a while. I do this...AND I make sure that when the film holder is inserted it is fully seated by pressing in on the GG back...keep the dark-slide-out-time to a minimum...and be careful when removing and inserting the dark slide not to disturb the seating of the holder. Touch up any place that the flat black paint is worn off...and smooth out any rough spots on the holders on the end where you insert the cut film. This all works for me...there may be others on this forum with some even better ideas. Info on converting to a Graflok back will have to come from someone more knowledgable than me. If you go back thru the 8 pages on this forum, there is some material on this. Regards, Fred.

alex · Joined: 09 Oct 2002 Posts: 6 Location: Seattle

Eureka! I took the spring back off as you advised and did the darkroom and flashlight test, waiting a good five minutes for my eyes to get accustomed to the dark. No light leaking around the holder at all (I tried several different types) - but definitely a small light coming through the little hole where once the little arm for the rear element of the sports finder used to be attached. I've now put in a small screw to block up this hole until I can locate a spare finder, and think that this will fix the problem. I'll run some test shots this weekend. Thanks very much again for this advice, which got me thinking in the right direction!

45PSS · Posted: Sat Oct 26, 2002 3:48 am Post subject:

The springs were bad on my Meridan and I ask a machinist friend and he got me some spring stock thru another machinest. Although it is blued, and thicker than the origional, I was able to make a decent functional set of springs. I wouldn't be suprised if SK Grimes could get you some spring stock. Pull should be 15 to 25 pounds to hold film holders correctly.
Charles

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The best camera ever made is the one that YOU enjoy using and produces the image quality that satifies YOU.