As I entered the world of 6x7 format through the Pentax 67+ a 55mmf4 and a 165mmf2.8, I got a 5 roll stack of Velvia 100. I was thinking of the 1 stop bonus when buying. Is there any difference in color palette/contrast/grain experienced by you between the "real" Velvia 50 and the Velvia 100 in 120 format?