Day/Night doublle exposures

[Rick Preston]

I have been doing some multiple exposures on one sheet of film and have encountered a problem. I make an initial exposure of a scene in the daylight, leave the camera in position and go back at night to add light, using various light sources. This is landscape work, so there is some temperature change, although sometimes not very much. The problem is registration between exposures. I have pretty much eliminated camera movement as the problem. The registration problem seems to be more exaggerated at the edges.
Anyone know if the film base is expanding or contracting with temp change?
This effect is very repeatable and is driving me crazy. I'm about to resort to doing separate sheets of film for the two exposures and combine in photoshop, but I want to stick with traditional darkroom.

[cjbroadbent]

It bows with humidity. Slip a fuzzy filter in front of the lens before doing the lights.

[Rick Preston]

Christopher,
Thanks for the suggestion. That would work for some applications if I want soft light. But Sometimes I want the daylight branches/blades of grass to be highlighted by my night illumination. I will try your suggestion, for sure, on some pieces.

[Samuel Burns Landsacape P]

def sounds like the film popping or bowing.

Before you make the first exposure in the daylight remove the darkslide, give it a tap against your arm to "knock" the film into a settled position in the holder. Then let the film sit for 5-10 minutes to equalize before triggering the daylight exposure. Hopefully in this time the film will have bowed or "popped" as much as it is going to and thus will have minimal movement during the waiting period until the night exposure.

I do this for all my long exposure work and have not had any issues with mis registration/doubling etc.

Cheers
Sam.

[Samuel Burns Landsacape P]

Another option - vacuum holders, here's a link for a DIY one

http://www.deadbread.com/crumbs/vac.html

good luck!

[poco]

I think the problem is shrinkage and not bowing or popping. If you're getting more ghosting in the bottom of the image than in the sky area, it's shrinkage for sure since gravity keeps the neg seated and the upper regions shrink down to it, going further out of whack.

I'm at a loss to think of a way to avoid it, though.

[Kirk Keyes]

I think the problem is shrinkage
I'm at a loss to think of a way to avoid it, though.

Viagra?

[Tintype Bob]

VIAGRA???????? I only use that to keep from rolling off the bed.

[windpointphoto]

VIAGRA???????? I only use that to keep from rolling off the bed.

Take a 1/4 of one to keep from peeing on your shoes.