It does seem to give an increase in film speed by about a stop but I still shoot it at 25. Better shadow detail and higher accutance than I was getting with Technidol. Grain is still super fine. Gene Crumpler left a thread somewhere in here about his experiences with Diafine. It was about a thousand years or so ago and I can't find it. If anybody can dig it up let me know.(posted 8930 days ago)