Tech Pan has an RMS grain rating of "5," APX 25 is a "7," and TMX is an "8," so Tech Pan has the edge in grain. It has an even greater edge in resolution: Tech Pan has a low contrast (1:6) rating of 200 lp/mm vs TMX's 125. At high contrast (1:1000), TMX and APX 25 both claim 200 lp/mm while Tech Pan is at 300.(posted 9521 days ago)Regarding contrast: developed in Photographers' Formulary TD-3, Tech Pan gives very smooth results at an ISO of 50. APX 25 is very close developed in XTOL 1:3. For me, TMX (in XTOL 1:3) is a definite third. While grain is similar to APX 25, TMX seems to have less exposure latitude and a bit more contrast, making it touchier to work with.