In the past I have used velvia 50 and provia and I know the difference; recently I made a side by side comparison between old velvia 50 and new velvia 100 as stated in a recent post. I heve sometimes used inthe past velvia 100 F but had no opportunity to do a side by side comparison between these 3 velvia sisters. Can someone of you share his opinion about difference between the 3 version of velvia? P.S. In my recent side by side comparison I used Provia 100 F too, with my surprise it is more contrasty than velvia 50. It is possible? Or it could depend from the fact that it was developed from another lab?