larryepage Loc: North Texas area

If you consider why photographs curl over time, it will help you remember why it is important to proceed gently, carefully, and with great caution when seeking to straighten them. It it also why it is important to follow Ed's direction and to be prepared for unexpected and damaging results as you proceed.

Any material that warps or curls does so because one side, for some reason, gets ever so slightly larger than the other side. If that expansion is uniform (or somewhat uniform), the material will "cup." If it is greater in one direction than the other, then the material will curl, or "roll," as the photographs in your photograph have done. This happens because paper has "grain," caused by the fibers aligning with each other as the raw materials pass through the paper-making process. That alignment is generally along the direction of the movement of the material through the process. This grain is why paper will almost tear more evenly in one direction than the other (most easily demonstrated with newsprint).

Anyway, over time, paper absorbs moisture and expands. There is more strength along the grain than across it, so the paper expands significantly across the grain, but very little along it. "Cured" photographic emulsion is a more plastic-like material and does not expand. The result is that the paper rolls up around the its long dimension. (In most cases, paper grain is intentionally aligned with the long dimension of the paper. Grain dimension is usually communicated by the dimension that is printed last on the labeling.)

The expansion that causes this rolling is generally permanent...you can't shrink the paper back to its original size. So that leaves two choices. Either you can find a way to "squeeze" the paper back to its original dimension (it will be an elastic process) or you can try to ever so slightly stretch the emulsion to allow the photograph to lie more flat. By the way, this is one of the primary reasons that proper archival presentation and storage of photographs is so important. The process of dry mounting seals the back of the photograph from moisture (the emulsion mostly seals it from the front) which mostly stabilizes the dimensionality of the paper substrate. Storage in a cool, dry place is a secondary way to reduce problems. And no, resin coated (RC) paper is not the archivel answer. There is a whole list of reasons why RC prints are not archival.

So in summary, understand what is going on, follow Ed's direction, and know that recovery is sort of a last-ditch recovery effort. It may or may not work. There are no guarantees.

Good luck as you proceed.

Architect1776 Loc: In my mind

Thank you for this great real life information.
I will remember this.

fetzler Loc: North West PA

Some years ago, I wrote to the George Eastman House on how to do this. As I recall the photos can be placed in a plastic container that has a layer of water on the bottom. Photos are placed on a rack (nothing that rusts) above the water for a few days. You are trying to created a humid environment. The container is of course is sealed. The paper will relax and could then be put in a print dryer or between layers of cloth and pressed flat. Placing a few real copper pennies (before 1982) in the water will inhibit mold. You should be done before mold becomes a problem, however.

Confirm with the George Eastman House.

Jorgy

Unless they are RC paper, in which case they should not have curled, I would try a "dry" iron and then put in a book while they cool. In the old days, I used flatten curled prints before dry mounting with the dry mount press which is just a big "dry" iron.

User ID

Absolutely NOT !!!

Great way to transfer some of the emulsion offa the paper and onto the glass. You may have see old prints suffering that problem cuz they were framed flush to the glass (no matte).

RodeoMan Loc: St Joseph, Missouri

How much would a heated drum press, even a used one cost?

bluezzzzz Loc: Stamping Ground, KY

$95.00 on ebay and it's yours! lol!

https://www.ebay.com/itm/Heated-Drum-print-film-dryer-with-cloth-apron-for-darkroom-development/231040642271?hash=item35cb186cdf:g:2GIAAMXQb2JSGrQU

Marshall

RodeoMan Loc: St Joseph, Missouri

Thanks, do you want me to pick up one for you while I'm getting mine? haha.

bluezzzzz Loc: Stamping Ground, KY

I guess I'll have to pass on that, I just like to look up stuff on ebay!

Way, way, back in the day when I had a darkroom, I dried prints in the way User_ID mentioned; on racks of plastic window screening.

Marshall

Gilkar

Mr. Shapiro seems to be the only one who has good. (and dare I say, intelligent advice). He is spot on with his suggestions. It is very dangerous to try and uncurl old fiber-based prints. The gelatin has dried out and will crack no matter what chemical you use. Steaming is the only successful solution I have used and I have been in this business for over fifty years. (Not that that means much but it does allow me to assume some expertise). That being said, steaming will soften the gelatin so exercise some care even when using this method. Print Flattening solution was never meant to rehydrate old, curled, dried-up photos. Its purpose was to allow fiber-based prints to flatten naturally after being heat dried on a drum or a ferrotype plate.

Ron Dial Loc: Cuenca, Ecuador

I had to flatten some silver nitrate cellulose negatives and prints from 1890's. Use two pieces of 1/4 inch glass. You can use a little, repeat LITTLE heat, but be gentle and patient. Takes about 1 month per image.