I think you hit the nail on the head Lex - Apparent sharpness requires some grain. There are ideal formats/film-types/developers that will have a favorite print size for sharpness. I find that for what I do in 35mm looks great in a 5x7 and good in a 8x10 and then after that it is too grainy for my taste for most of the images I make - for 6x6 it is great in a 8x10 - good in a 11x14 and often acceptable at 16x20. But this is all considering the film and developer choice. Pyro makes bigger grain than Microdol no matter how masking the stain is and that sets up the enlargability of the negative -
Of course 4x5 negatives always print good! g

Quote Originally Posted by Lex Jenkins
So up to a point we should be printing at a certain ideal (yet undetermined by me) size that would overcome the grain pores of the paper, yet would not exceed the limits of the negative.

Make sense? If not, feel free to dig in. This is just my pet theory backed up by nothing more than personal observations.