I have found that condenser enlargers make prints that appear sharper then diffusion enlargers. I also find that high accutance negative developers enhance the appearance of sharpness - As fas as paper goes - The sharpest looking images usually seem to be on contrasty ferrotyped FB or glossy RC papers although I find un-ferrotyped glossy FB and mat FB to be more desireable overall. It think the appearance of sharpness has less to do with lpm and more to do with grain and accutance. Tri-x has a gritty grain that looks very sharp although when developed in D76 doess't break any records for resolution. Tech pan may have the greatest resolution but may not always look sharp.