I've never used Delta 100, but would assume that it's sharper than Plus-X just due to being a slow t-grain type. Anyway, FWIW, I've always had better results with Plus-X in D-76 straight, rather than 1:1. No idea why, or if that experience agrees with anyone else's, but it cleared up what I always thought were rather flat and mushy looking results.(posted 8370 days ago)