How long before 4x5 sags?

[couldabin]

Does anyone have experience with long delays (>2 hours, say) between removing the darkslide and exposing the film? My camera will be set for landscape mode, and horizontal (the film holder will be vertical). There may be instances in which several hours elapse between removing the slide and taking the photo. I'm certain this will help expose any light leaks (so to speak) in the camera, but I'm also wondering about whether the film (probably FP4) will remain flat for such long periods.

 

[David H. Bebbington]

I have plenty of 4x5" experience but none with this problem! However, off the cuff I would say that the darkslide has no function in keeping the film flat, only in keeping the light off the film, so leaving the film holder with the darkslide removed for a greater or lesser time should really have no effect except to expose the film to ambient air. If this was extremely humid, I guess you could have a problem, but then I would expect condensation to be a bigger hazard than film flatness.

 

[David A. Goldfarb]

If you're concerned or if tests reveal that this is really a problem with the filmholders you have, you could put a piece of double stick tape in the center of the filmholder septum. It's probably not a good idea to leave the film loaded this way for a long time, though, so load before the shot, and unload right when you're done.

 

[Konical]

Good Afternoon, Duane,

Just before inserting the holder into the camera, give it a tap or two against your hand. Position the holder in the same direction (horizontal or vertical) as your intended shot. Usually, the film will settle to its lowest position within the holder. I have also used two or three layers of very tiny pieces of plastic tape on the flap portion of the holder (in the extreme corners). These will press tightly on the film when the holder is in the camera. Generally the tapping method should take care of the problem.

Konical

 

[couldabin]

Thanks for the advice/observations. I'll post something about the outcome (likely several weeks away still ...)

 

[Vaughn]

I'll double Konical's suggestion...

...about tapping the holder. It is also a good way to make sure any dust or hairs fall down into the sky portion of he neg during exposure. But keeping your holders clean and hoping that any dust will actually fall all the way to the bottom is better than having a negative move during a long exposure! I have lost a few 8x10 negs that way!

I have used the double sided tape -- it does work, but increases hassles of the loading/unloading procedure significantly. The idea of the tape on the corners of the flap sounds intriquing!

Vaughn

 

[Konical]

Good Afternoon, Vaughn,

I expect you're right about the dust. I didn't have a problem with that, but I do try to be thorough in using the Staticmaster brush on my film holders. I also tend to use the tapping approach mostly for long-exposure situations (night shots). When the sky portion is black, not much shows up anyway.

Konical

 

[Curt]

The procedure I was taught at Brooks was to give a light tap so the film wouldn't shift during exposure. When cleaning the holder, using a brush, brush the holder and give it a tap to dislodge any particles from the light trap. It's not over done just consistent.

Curt

 

[pgomena]

The double-stick tape technique works really well. As for the dust, I put my cleaned and loaded holders directly into a quart-sized ziplock baggie immediately after they're loaded. I used to assist for a guy who tapped the holder against a finger on the other hand automatically before inserting it into the camera. It was part of the ritual.

Peter Gomena

 

[Poco]

Using double sided tape works, but can make unloading tricky because any kind of quick, sudden release off the tape can leave a dark mark of added density on the negative. I don't know if the tape sparks or it's a question of heat from sudden release, but it can screw up a negative big time.

Once a 4x5 sheet is properly seated by tapping the film holder, it won't sag ...but it will shrink if the ambient temp is cold. So in winter you should wait a minute or so after pulling the slide and before opening the shutter. But that's not likely to be a problem for you. In your case, where the darkslide has been pulled a hours ago, I'd simply return to the camera and give the ground glass a couple light taps with my finger tip before making the exposure -- something I do even if I've tapped the film holder before inserting it.

 

[couldabin]

I've never tried the tape trick. Hopefully, the film will stay in place without it. Thanks for all the input.

 

[Maris]

I used to suspect film sag but discovered that the problem was really tripod settling.

I do double exposures of sunlight dappled forest scenes with the first exposure for the sunny patches (zone VI 1/2) and the second, maybe an hour later (just after sunset), as an overall zone V.

Every time the tripod is set up on grass, leafy forest floor, fern clumps, or anything organic it WILL settle and the two exposures will be slightly out of register. Now I make the tripod legs burrow down until they are lodged in solid earth. No more double exposure woes.

 

[Vaughn]

Good point, Maris...

That could very well be one of the causes...tho not as likely with some of my problems. My camera, lens and tripod together weigh about 15 kilos (33 lbs), between the weight, the spiked tripod feet and the 15+ minutes set up time, I don't think settling is my particular problem.

I have seen two types of negative movement problems with my 8x10 -- a bowing (double image only in the center of the negative), and double images that get worse as one moves away from a corner of the neg (one corner with no double image -- indicating that the neg was in slightly crooked and settled by pivioting on one corner.)

However, your suggestion is very good and must be taken into consideration.

vaughn