F = For older Fujichrome Astia/Sensia/RTP II and Provia films. Exception: Use N3 for new Astia 100F, Provia 400X, Sensia 100 films prod. since June 2003
N = For Astia 100F, Velvia 100/100F, Provia 400X and Sensia100 films prod. since June 2003
V = For old and renewed Fujichrome Velvia 50 film