While ripping up some poor Velvia 50 and Velvia 100F exposures, I noticed the Velvia 100F could not be torn. The best effort in the world could not rip it. I had to resort to sissors to cut it up. The Velvia 50 tears very easily. Does anyone know why the 100F is so tear resistant? I do not recall reading that anywhere. What kind of base is the 100F? Are there disadvantages to the 100F base material?