something that can effect the sharpness of the finish product; film developer that was used.
This is my personal experience and i am sure others who have more specific knowedge of chemistry can chime in with specifics.
i ran a series of test with a friend of mine. we took 4 images and made 8 shots each and then developed half in one developer, half in the other; including a -N, N, N+1 and then N+2 times.
the negatives developed in pryocat hd and used to make both van dyke brown prints and palladium prints were signficantly sharper with every paper tested.