I love Arista.EDU Ultra, and have used it in every size from 35mm up to 4x5 and in 100 and 400 speeds. PDH is right - it's Fomapan. It is conventional grain, not T-grain, but finer to my eye than the sometimes grungy look of Plus-X or Tri-X. Compared to TMX, I'd say TMX is finer and smoother, but Fomapan is nice and smooth in the midtones.