Tri-X is an older and more forgiving emulsion with a somewhat coarser grain structure. T-Max 400 has an H&D curve with little shoulder, which means it tends to compress the high values. It therefore requires much more careful development than Tri-X. People generally recommend that beginners stick with Tri-X. However, if you work carefully and always develop your film in exactly the same way, there is no reason you cannot get excellent results with TMY. I can usually get a true EI of 400 out of TMY, whereas my EI with Tri-X is about 250.(posted 9145 days ago)