light leaks using Grafmatic holders

[pound]

I just got a used grafmatic holder and did a test shoot today. all 6 sheets suffer from light leaks of some kind. I wonder is it due to operator problem or it is the holder problem?

The 1st 2 sheets are better but the area where the notch is suffer from light leaks
for eg (photos has been crop to reduce size) :

http://farm8.staticflickr.com/7137/7662206612_0c585b5f37.jpg (http://www.flickr.com/photos/26920982@N02/7662206612/)

the other 4 sheets suffers from a band of light leaks at the notch end:
http://farm9.staticflickr.com/8003/7662207360_b46112bba2.jpg (http://www.flickr.com/photos/26920982@N02/7662207360/)

any advise? thanks.

[Chauncey Walden]

You are returning the darkslide to the shell before shooting, right?

[pound]

You are returning the darkslide to the shell before shooting, right?
thanks .
after googling, I realised i should lock the graflok back after putting in the Grafmatic. I didn't and that might have caused some light to leak in. I tried again this morning and there wasn't any light leaks. thanks for yr help.

[Michael Cienfuegos]

thanks .
after googling, I realised i should lock the graflok back after putting in the Grafmatic. I didn't and that might have caused some light to leak in. I tried again this morning and there wasn't any light leaks. thanks for yr help.

Don't feel bad, you aren't the first one to make that mistake. :o

[David A. Goldfarb]

If you are slipping the Grafmatic under the groundglass like a normal filmholder, it should not be necessary to lock the Graflok slides.

In the top photo the top of the image is out of focus, which could have a number of causes, like using too much rise with a lens that doesn't quite cover the format sharply (150mm tessar-types, for instance, or a 90/6.8 Angulon), but given the light leak issue, it could be because the holder isn't seated properly or isn't fully inserted into the back. There are some cameras that have an obstruction that prevents the Grafmatic from being fully inserted, so you might check that it's going in all the way.

Chauncey Walden's suggestion above about re-inserting the darkslide is also important. I would recommend the following sequence: close and set the shutter and aperture, insert the Grafmatic, pull the darkslide and reinsert it behind the top septum, make the exposure, advance to the next sheet.

If the shutter is open while you pull the darkslide, then light will leak through the notches of all the septums, depending on how bright the ambient light is, what the aperture is, and how long you leave it like that. So imagine the worst case scenario--you're shooting outdoors on a bright day with a fast lens, and you left it wide open, inserted the Grafmatic, pulled the darkslide without reinserting it, got a phone call, started browsing lfphoto.info on your smartphone, closed and set the shutter and made the exposure--the whole stack will be fogged around the notch. Then say you're shooting a still life indoors, and you're stopped way down, and you've closed and set the shutter, and you're shooting slow film, and again, you pull the darkslide without reinserting it, make the exposure, then advance to the next sheet--you might not notice any significant fog, despite following the wrong procedure.

[Frank Petronio]

What David said but also in general, the Grafmatics are heavier and tend to pull the backs out away from the camera, causing small leaks. Also if they are not seated absolutely flat against the back, they can leak. I'd inspect the back inserted into the camera and make sure there is no wobble.

When using them, it is a good habit to keep your second hand pressing them in towards the camera whilst pulling on their slides.

[pound]

thanks David and Frank for the further input. Very good tips.
come to think of it, i might have not close the shutter (was using an synchro compur shutter on Bulb mode) before moving the dark slide.

[patrickjames]

I can only echo the above comments. One thing not mentioned is to check the felt pad at the end of the Grafmatic. I had one in which the pad was folded over that I would have to assume caused problems because it was fine after I re glued it. I don't know what it is there for. I assume some type of light trap for the end of the septums. IIRC it had the same effect yours is exhibiting. It was a few years ago though so I could be off with this but I thought I would throw it out there.

[Jim Andrada]

+1. +2. +3 on locking the Graflok sliders on the Grafmatic. I know you "shouldn't" have to but my experience has been that all the pulling and pushing will wiggle the holder around and often even push it out of place/move the spring back/etc.

Best thing I ever did to minimize light leaks was to always engage the Graflok sliders.

[al olson]

...

Best thing I ever did to minimize light leaks was to always engage the Graflok sliders.

Amen!