The ideal, I think, is drying on fiberglass mesh screens (mosquito net!) and flattening with a dry mounting press (and cooling down under the same press and storing in a proper way).
As far as I understand the prints curl because of the edges are drying faster than the rest of the print; this leads to some kind of tension in the paper base and the print curls. With this in view I use a combination of several methods: fiberglass mesh screens, blotters, an ordinary flatbed print dryer, and a press – I use an old fashioned plant press, but other solutions is of course possible. The rest sounds complicated, but works quite good and now almost second nature!
The prints are squeegeed and put face down on fibreglass screens; on top some layer of acid free blotters to avoid too much curling. The prints should not be entirely dry at this stage of the process, it is enough that they can be put face to face without sticking to each other. When dry to that extent it’s time to use the plant press. Normally I make my prints on 91/2x12 in. papers, so I have cut some acid free blotters to the same size, and I use them between pairs of the prints put face to face, thus making up a bundle with prints and blotters (and blotters on top and back of the bundle as well) that is put into the press.
After some hours in the press the moisture in the prints seems to be more evenly distributed and the prints in fact entirely flat–but off course still not completely dry! In fact it will take weeks for the prints to dry in the press! So, it’s time to use the electric print dryer to squeeze out the remaining moisture in the prints. The dryer can be quite hot and the print is completely dry within a minute or so (putting your hands on the canvas of the dryer you will easily feel when the print is dry!).
It would be nice if this was enough, but unfortunately it is not! The very dry and now more and less hot and quite flat print should cool down in the press, and for the best results, in my experience, between the blotters which probably contain a rest of moisture and thus gives the print some kind of normal humidity. After some hours in the press the process is complete and the prints are flat, and they will stay flat, if properly stored.
I have explained my method to some friends with print curling problems who responded by investing in a dry mounting press! Maybe they made the right decision, but I think my method works quite nice – at least for me.