Just acquired a Speed Graphic with spring back and 135/4.7 Optar. The bellows look clean and in good condition, although I haven't yet had the camera apart to have a good look at it. I took a few test shots with it, using 2 different dark slides, and all of them have what looks like a light leak. Here's 2 examples:





Anybody have any suggestions as to the most likely culprit? I'd like to try to fix this myself, although I'm no great expert at camera servicing, so suggestions as to what to look for would be very helpful.

Thanks.

Ian

Find a mini-maglight.
Find a dark or at least semi- dark room.

Remove the back: two screws on the springs if it's a Graphic back, push and slide the chrome arms if its a Graflok back.

extend the bellows as far as possible. remove the front lens board.

take the head off the mini-mag light and stick the light bulb inside the bellows.

Look at the outside for pin holes.

Note: Pinholes find the tiniest cracks and corners to propagate. Move the light around and into the corners (the small bulb doesn't get hot enough to hurt anything.

Another option is to use a compact fluroescent bulb on an extension cord.

I suspect it's a pinhole because the fog in the second image is an image, and I suspect the first neg's fog is a partial image too.

Either that or this building was built on an ancient cemetery and this is just the beginning of what will be a great movie.

Thanks Les, that's very helpful. Will give it a try over the weekend.

I haven't tried Les's method, but sounds like a good one. I use one of those old elongated fishtank bulbs in the dark room. Same drill. That's inside out. For outside in I use bright light like a Mag or the spot on my headlamp. You'll want to light test with the film holder you used in place, and look towards the back with the lens board removed.
Check everything out by process of elimination. You can put film or paper in holders and put out in light to check for leaks on the film holders also. There 's info here and elsewhere on a good method for that test.
Another culprit I found once that looked something like film holder light streaks turned out to be very small cracks in the lid of my daylight developing tank. The reason I mention this and to check other issues is that small pin holes in the bellows aren't that big a deal. Just keep dark slides in until ready to expose and replace right away. Your images have a look as if maybe the film holder is either not seated flatly in the camera back, or lifted when pulling the darkslide etc... Hold the viewing screen firmly against the camera back and holder when pulling dark slides.
Just some added thoughts for you to check...
Have fun.

Thanks again.

I've done the light test and found a couple of pinholes, so tomorrow I'll find some suitable vinyl repair gloop to fill them.

Many thanks for the help, really appreciated.

Great, a couple more test shots are hanging up to dry and it looks like the leak is fixed

So what did you use for the "gloop"? (not that it wold be available over here...)

This:

http://www.halfords.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10151&storeId=10001&partNumber=526483&langId=-1&cm_mmc=Googlebase-_-Body+Repair%2FTapes+%26+Glues-_-Na-_-Loctite+Superflex+Silicone+Sealant+Black&%24%24tid=zBScBDK9oBBxaEZHq7c9oLLVC-wvyxAxIRgsGiNqpo0bOe_0DXXApGcukAfG0I-1

and then covered the repair with black electrical tape. Seems to have done the trick.

Thanks. That link is so long that it ate my computer---twice! Even converting it to TinyURL was no help. I'll google up "halfords" and take it from there. Glad your repair was effective!

The Loctite 5940 Black Silicone sealant is an excellent choice for patching small holes in the vinyl bellows, however the tape will come off in a relatively short time and leave a very sticky, hard to remove residue that will migrate onto adjoining areas and your fingers. I strongly recommend you remove the tape now and clean any residue off. Window cleaner such as Windex or Isopropyl Alcohol will work well now. Black fabric paint applied to the inside of the bellows works well also. Use the washable kind if available.
Plasti Dip is another product that works very good for vinyl bellows repair.

Thanks for the warning about the tape.

Equinox Photographics have bellows repair stuff too. Go to http://www.equinoxphotographic.com/large.htm and scroll down to the pink/purple text, about 2/3 down the page. $6.50 + $3 postage in the US, obviously more to the UK.

Cheers,
Bruce