Both contrast and color balance could be influenced by how the negatives were turned into Web images -- negative scan, traditional print and then flatbed scan, or something more exotic.

As to the grain/reticulation, I seem to recall hearing that radical pH shifts can also cause reticulation, but these have to be pretty extreme. I've heard of people processing ECN-2 films in C-41 without getting such effects, so I doubt if this is a factor, but I thought I'd toss it out anyhow.