Quote Originally Posted by Rick A View Post
The malady the OP is obviously refering to is called "cupping". The cause is the emulsion layer being a different substance than the base of the film, when dried it shrinks more than the base material. I have a feeling that some with this excessive problem have probably left the film in liquid for longer than necessary, causing more expansion initially, resulting in excessive shrinkage upon drying. I shoot Chinese film that most complain that it cups and curls, but have personally experienced minimal signs of it, Foma does exhibit some tendency, Ilford, Fuji, and Kodak almost none in my experience.
Your geographical location makes a huge difference, because it's humidity related. I live in Minnesota, which has some of the biggest differences in humidity in the world, comparing summer to winter. Bone dry like the desert in the winter, and often 90% or more in the summer.

In the summer my negatives dry flat, and in the winter they don't.