Testing Film Holders

[Fungus]

I just bought a bunch of used 4x5 film holders on eBay. What’s the best way to test these for light leaks?

[diversey]

Photo paper.

[gypsydog]

Buy a box of cheap CatLabs X80 film, load the holders and expose them to prolonged light, develop film keeping track of which holder it came from.

[popdoc]

Photo paper


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[Vaughn]

Number the holders, load with film, and start using them. Note any fogging when developing the film.

Holders have to be pretty beat-up to leak light...and unless you have a lot of time on your hands, I would not bother testing. But photo paper in bright light would be the way I'd go about it. But while you are at it, stick a new-to-you holder in the camera in the sun, stretch the bellows out, and leaving the lens closed, remove the darkslide for 15 minutes, and see how your camera is fairing.

[John Layton]

photo paper is not sensitive enough (IMHO)...gotta be film!

also see if the holders lie flat when placed on a flat surface with the ribbed spline hanging free over the edge. If perfectly flat...great! If not, then insert into film holder and look back into bellows (lens removed) under dark cloth while bright light shines obliquely towards back end of camera and make sure that film back spring tension is more than enough (reaching back to push the projecting end of the holder backward until light just starts to enter) to straighten out those holders!

[Tin Can]

If wood, warpage is common in not stored flat or UP

Be careful how any DDS is stored

[jnantz]

fungus

get some bookbinders tape, you might have to re-tape the hinges

[paulbarden]

Number the holders, load with film, and start using them. Note any fogging when developing the film.

Holders have to be pretty beat-up to leak light...and unless you have a lot of time on your hands, I would not bother testing. But photo paper in bright light would be the way I'd go about it. But while you are at it, stick a new-to-you holder in the camera in the sun, stretch the bellows out, and leaving the lens closed, remove the darkslide for 15 minutes, and see how your camera is fairing.

+1

[Alan Townsend]

fungus,

1. Examine and clean the holders using compressed air. If any are really sticky, soak in warm dish detergent/water, rinse and dry. Cull crummy ones.

2. Test with cheap xray or ortho litho films or enlarging paper. Place outside in shade and leave for ten minutes or so on each side. A little longer with paper. Process and check. Or just use them and see if they work OK.

3. Using a shim that is 3/16 inch thick (.1875 in.), check this critical dimension to ensure correct focus. Many newer film holders may be off. Older ones not so much. Put the shim against where the film goes, and make sure the front of the holder is in the same plane as the top of the shim using a straight edge and feeler gauge if you have one.

Lock, and load. I mean unlock, load, then lock and go shooting. :)

[Vaughn]

photo paper is not sensitive enough (IMHO)...gotta be film! ...

One way around that (and should not be a problem, anyway, IMO) is to flash the paper to a very light gray. This takes the paper off its 'toes' and one can see any low-level fogging as easily as with film. Film does have the advantage of already being cut to the right size, though!

I do not recommend getting the holders wet -- it can really muck up the light trap felt. Found that out when a student tried to develop film in the film holder.
I believe the hinge tape does not function as a light-blocker...the holder is itself constructed to do that with light traps.

[Mal Paso]

Most of the modern plastic holders have a metal core to prevent warping. The felt either side of the slide can be a weak point but you would see any other defect that would cause a light leak. As was said hinge tape won't leak light as the tab interlocks.

I have no wood holders and one all metal 4X5 holder. Can't remember if it's aluminum or steel, will have to look

[Mark Sawyer]

As said, photo paper. Set the holders out in the sun for a half hour, flip them for another half hour, and develop. If they leak, you'll see it.

[LabRat]

The leaking "usual suspect" is in the slide light trap... If the felt is too worn or trap spring got weak, the trap will not close completely when slide is removed... You can check for this by removing slides, bring holder into darkened room and shine a bright flashlight into the film chamber towards the trap, cover the light beam so you can only see into the outer slide area, and look carefully to see if you can spot where there might be a sliver or ghost glow of light you can see... Repeat this with all your empty holders...

And it is a good time to use a shop vac with a fine filtered collection bag and nozzle attachment to suck clean every nook and cranny of holders + slides... And can wash all the slides one at a time with dishwashing detergent to remove old crud... But put all slides back into the same holders as slides can vary between age, wear, and make of different holders... Then store in anti-static bags before/during/after use...

Also, if you get a # of old holders, first vacuum the outer slides & grooves before pulling slides for the first time, as the possibly dirty outsides could pull dirt into the light trap...

Good luck!!!

Steve K

[Martin Aislabie]

As said, photo paper. Set the holders out in the sun for a half hour, flip them for another half hour, and develop. If they leak, you'll see it.

This is what I did.

Put the film holder in the camera and pull out the darkslide (while it points at the sun) to check the light seals work OK.

Martin

[Mark Sawyer]

I'd set the holders in the sun without being in the camera to maximize the chance of leaks. Being in the camera may block a leak that will cause problems. The number one problem in light leaks is not seating the holder correctly in the camera, but leaky holders leak most while being handled outside the camera. But at least you know there are no light leaks in the camera!

[Mal Paso]

If you want check a camera or holder light trap, make up a lens board with a 10W household LED on the inside of the camera, put in a film holder and inspect it in a darkroom or dark room.