Film buckle or saging during exposure

[Gudmundur Ingolfsson]

Last week end I was photographing inside a large concrete tank lit only by daylight coming though two manholes. I was shooting on 8x10 B/W with a 150mm wide angle and because it was difficult to focus I used f 32. I exposed 14 sheets at 1 min, 2 min and
3 min. Only the three sheets that were exposed 1 min were sharp. All the other although
correctly exposed were moved, some only partially. Have you experienced this?
Are some films less likely to buckle ? I was using may favorite for this kind situation Ilford HP5 but at longer exposure times than usually.

[vinny]

one thing I always do is tap the holder against something before placing it in the camera to get it to sit at the bottom of the holder.
you can make you own sinar type sticky holders by getting repositionalble 3m atg tape and placing that in your holders. Of course to make loading easier, you'll have to remove the plastic that normally holds the film in. I think any film will buckle under the right conditions, temperature changes being one of them.
Next time, focus using led flashlights if you can and shoot at a faster stop.

[Arne Croell]

Yes it happens, even with 4x5 and including tapping. If the temperature, but more important, the humidity of the place is much different to that in the film holder, the emulsion can swell or contract while adjusting to the new conditions, leading to some movement. Wait a few minutes with the darkslide drawn before the exposure in that case.

[Gudmundur Ingolfsson]

Thanks! Now I have a good explanation. There was much water, I was wading knee deep. And the sharp ones were maybe not the 1 minute ones, but the ones I waited for a few minutes till sun rays had gone with the darkslide pulled. You are always learning even after 26 years of 8x10".

[Vaughn]

This happens often enough to me to be a bit annoying. Seems like most of my exposures are in the multiple minutes range (up to 30 or so), in cool humid air of the Redwoods.

Tapping well before loading does help. Letting the film have time to acclimate for several minutes - done that, seems to help. Having the camera pointed upwards helps but not always possible. I put thin two-sided tape in the holders to hold the film down (more trouble than it was worth, IMO).

But now I just live with the fact that occasionally, when I mess up or when the atmospheric conditions go loopy, I am going to lose a negative.

Vaughn