Dark Slide Masking

[bieber]

In curious to hear about experiences any of y'all might have with making double exposures and masking parts of the image with partial dark slides. I'm thinking about making a half dark slide for myself by cutting a piece of trophy aluminum to half the width of my dark slide and using it to shoot half of a plate at a time, but I'm worried about making it precise enough to get a crisp dividing line in the middle. Any tips?

[Vaughn]

I have made such modified darkslides for 8x10 and 11x14. I have used a couple types -- I prefer the metal darkslides (they last longer in my pack than the stiff plastic ones!)

I cut them with a fine bladed coping saw and smooth them out with a file.

Never any problem with the 8x10, but had issues with the one for 11x14 -- too many brands of old holders (Hoffman, Sterling, S&S, Fidelity). I used a Fidelity darkslide -- would not even go into the S&S. Some light can leak in when the light trap is only partly being used (only with the 11x14). I'll use the darkcloth better next time to keep light out while inserting the modified darkslide.

The image of the two modified 11x14 darkslides is deceptive -- I did not get the edge quite as straight as it may appear...I'll just do a little more file work to correct it. The diagram is for an 8x10 Fidelity holder to get two 4x10s on a sheet of 8x10 film.

[bieber]

Interesting, yours is a little more sophisticated than mine. I had a go with the trophy aluminum today, and it wasn't the worst thing I've ever done. Not the best either. Getting the half-darkslide perfectly vertical was a challenge since I didn't have full width at any point for alignment, and on this one I got a little bit of overlap in the middle. On some previous plates I got the dividing line perfect, but those were all duds for various other reasons. At some point it'd be nice to try getting one CNC cut, although I'm not sure how much that costs...

181720

[Vaughn]

Another way is to install a movable baffle in the camera. Remove the camera back put in the baffle, put the back on, open the lens and you will be able to see if you have baffle lined up properly.

I have heard them called dividers, splitter boards, inserts and sliders. The Deardorff 8x10 has grooves to fit splitters to make two 4x10s or two 5x8s on an 8x10 sheet of film. Since the splitters do not involve the film holders directly, there is less chance of film damage. So you might be able to think of a easy way to modify your camera to take a homemade splitter.

[jim10219]

If you can cut out a square hole, instead of removing the entire half of the dark slide, it might make it easier to line up and insert. That way the dark slide still fits in both channels along the top and bottom (or left and right if in portrait orientation), and still fits into the tongue. That might be hard to do without a CNC machine or 3D printer though.