Warped ULF darkslides

[Gene McCluney]

I just acquired a few ULF film holders, and a couple of the darkslides are warped to the point they don't slide in well, and are "cupped" so they don't slide in the flap, unless pushed in with a finger. Can't do this when holder is on camera.

These are modern holders, not antiques. They appear to have bakelite dark slides. Was wondering if anyone has ever de-warped a dark slide? I am thinking dry-mounting press. I don't think it could hurt.

Opinions greatly appreciated.

[Don Hutton]

Reverse them for a couple of weeks and they will likely sort themselves out - I had the same issue with the darkslides on some 12x20 holders a few years ago and they flattened themselves out with the aforementioned trick and never were a problem again.

[Jason Greenberg Motamedi]

I had that issue with some Hoffman holders. I ran the slides under hot water and then bent them back to flat. I suppose if I was more patient I would have tried what Don suggested.

[sanking]

What Don said. Remove the dark slides and put them back in the holder with the opposite side out. This should reverse the cup of the slides over night, or in a day or two.

The warping appears to be caused by a sudden change in relative humidity that causes uneven expansion of the wood and phenolic plastic within a short period of time and puts pressure on the latter. In most cases it is reversible with the action I described above. They may cup again in the future in the opposite direction.

Sandy King





I just acquired a few ULF film holders, and a couple of the darkslides are warped to the point they don't slide in well, and are "cupped" so they don't slide in the flap, unless pushed in with a finger. Can't do this when holder is on camera.

These are modern holders, not antiques. They appear to have bakelite dark slides. Was wondering if anyone has ever de-warped a dark slide? I am thinking dry-mounting press. I don't think it could hurt.

Opinions greatly appreciated.

[Gene McCluney]

What Don said. Remove the dark slides and put them back in the holder with the opposite side out. This should reverse the cup of the slides over night, or in a day or two.

The warping appears to be caused by a sudden change in relative humidity that causes uneven expansion of the wood and phenolic plastic within a short period of time and puts pressure on the latter. In most cases it is reversible with the action I described above. They may cup again in the future in the opposite direction.

Sandy King

The ones I have are not only cupped, but twisted like a helix. I could barely get them out of the holders.

[RichardRitter]

If you can not remove the slide put the whole holder in a big trash bag and let it sit. I keep mine in big bags. The humidity is up one day and down the next. Keeping the film holder warped up keeps them stabled.

[IanMazursky]

One of the original Korona slides i have was badly warped and cupped from what i gather, it was water damage (before i got them).
I tried a bunch of things including a screw press but finally gave up and bought a new set from Sandy. They are fantastic, thanks again Sandy!
Im still wondering about the ancient slide i have. Maybe a trip through the dry mount press might work?

[Jim Galli]

Probably the ones you just got from me. I had the same problem with them when they got to me. Tonopah Nevada is unique. Our yearly average humidity is about 8%. I had to wait for those to acclimate, and eventually they did. Sounds like they are re-acclimating again. A cup at the bottom so the corners would catch first and guide the rest into the slot is a good idea.