Quote Originally Posted by PE
The M1 mordant is NOT compatible with gelatin or emulsions which are to be coated
Does this arise from the fact that it will harden it, resulting in a big blob of insoluble gelatin?

One patent that I know of is U.S.P. 2,952,566, assigned to Louis Condax (EK), Mordanted Photographic Imbibtion Dye Printing Blank.

Haven't actually read it yet..