Foam question

[dncswclds]

Being that I am new @ LF but many years @ 35/MF I have a small situation that needs help. I have seemed to be getting light leaks on my film. I took the back off to replace the foam and I realized that the foam only covers 3 sides. Should not their be something on all 4 sides of it ? The film holder may cover this but it may need foam in the grove that is there. Enclosed is a photo. Thanks of the assistance Dennis

112400

[Michael Clark]

No, that grove is a light trap that mates up with the notch rib on your film holders.

[Michael Clark]

Finding light leaks is not always easy.Putting a flash light inside the camera in a dark room helps to find some , there is also the possibility of the film holder leaking also.

[dncswclds]

Here is a photo of the leak. Consistently same place

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[dncswclds]

OH OH. Next picture different spot locationbut I guess the same as I have flopped the holder. I do have to change the seals as they are sitting in front of me ripped out of their place. I see one of them is very deteriorated in the corner.

112407

[Michael Clark]

The leak has the same shape but in differnt location. Load some photo paper into the holder and take out side with out removing the slides go back to darkroom and develop the paper. If its not exposed anywhere then your holder should be light tight and the camera might be suspect.

[Michael Clark]

dncswclds, after thinking about the light leak you have, it could very easily be the gaskets or seals around the area the film holder contacts the camera back.

[dncswclds]

dncswclds, after thinking about the light leak you have, it could very easily be the gaskets or seals around the area the film holder contacts the camera back.

That is what I suspected as well. It was in the same spot as the holder is flipped for the next photograph. I have the old ones removed already and I noticed one corner was severely damaged so I will replace them and try again. I have tried 3 of my holders and all the same. Thanks all for the responses. Dennis

[Doremus Scudder]

Being that I am new @ LF but many years @ 35/MF I have a small situation that needs help. I have seemed to be getting light leaks on my film. I took the back off to replace the foam and I realized that the foam only covers 3 sides. Should not their be something on all 4 sides of it ? The film holder may cover this but it may need foam in the groove that is there. Enclosed is a photo. Thanks of the assistance Dennis

112400

Don't put any foam or other material in the groove. It can/will keep the holder from seating properly and will likely affect focus and/or cause light leaks. Don't ask me how I know this :rolleyes:

Your leak looks like a separated seam on the side of the holder itself. Visually inspect the holder in strong light/with a flashlight with the darkslides removed and see if you can see a leak. The fact that the rebate of the film is light-struck really points to a holder defect and not the camera back.

Best,

Doremus

[Jim C.]

It's velvet fabric not foam, that seals the 3 sides.

[Jim Jones]

It's velvet fabric not foam, that seals the 3 sides.

Yes, and as Doremus suggests, if it is too thick, it may throw the focus off.

I usually drape the dark cloth over the bellows and camera back to reduce the possibility of such leaks.

[dncswclds]

Problem fixed. I purchased some Semi-new holders & a new Paterson tank and the photos turned out without the marks on them. Only thing was I developed at the wrong temp in Pyrocat HD. I just used the usual 20 C and when I went to DT time I missed the last part where it said 30 C. Learn from mistakes then you will NOT repeat them... Ordering another 100 x of Fomapan 100. Keep me busy through summer.

[Nissin]

Don't put any foam or other material in the groove. It can/will keep the holder from seating properly and will likely affect focus and/or cause light leaks. Don't ask me how I know this :rolleyes:

Your leak looks like a separated seam on the side of the holder itself. Visually inspect the holder in strong light/with a flashlight with the darkslides removed and see if you can see a leak. The fact that the rebate of the film is light-struck really points to a holder defect and not the camera back.

Best,

Doremus

Sorry to resurrect an old topic, but I'd welcome clarification on whether or not to use a seal in the groove of a Wista N back. I have to replace the velvet light seals and thought I'd replace the dried-out foam seal that is presently in the groove. The groove is 2 mm deep and the tongue on the film holder is 1 mm, so I was planning to use 1 mm foam to close the gap. Can I skip using foam, in this case?

Thanks.
Nissin

[LabRat]

If there's any gaps, re-foaming is a good thing...

Most foams are too dense to fit in a tiny gap, but if you try using a open cell foam like the kind used for air conditioner filters (that you can see through), when compressed, they will seal well filling a small gap...

If your velvet material is still mostly intact, you can patch the gaps using the light trap material from old 35mm cassettes, and patch in pieces as needed... Cut any joining pieces at 45 deg angles for light proof seams, and secure with a little contact cement...

Good luck!!!

Steve K

[Tin Can]

I use this (http://www.amazon.com/JVCC-FELT-06-Polyester-Felt-thick/dp/B003ZCTWSG) and cut it to size. Bought a 19mm roll years ago and it ages well.

The polyester felt is strongly attached to thin adhesive.and I notice no dusting.

At 1 mm it has fit in old Linhof LF cameras and used to seal Packard shutters with bad felt. Many uses.

I don't use if for tiny format cameras. That's foam.