I have done everything possible with the Rockland tintype and it just is no good, it sucks. The old stuff worked much better, I was told by one of the employees that the old developer had formalin (fermaldihyde) and it was taken out due to health concernes. The new stuff has no staying power, I used a batch that that I mixed up a few months ago and it worked fine for the first plate but all the rest of the plates had a flat dull contrast. I guess it will have to be collodion from now on.
I'm done with it!!!