its the same emulsion as rollei retro 400s. i found the true speed in most developers to be between 120 and 200. my favorite has been beutler 1+1+10 for 9.5 minutes. very high sharpness and acutance, great tonality and lowers the contrast a touch as this film can be high contrast at times. yeh, it does give larger than normal grain, but i get great sharp enlargements from 35mm up to 11x14. with 6x7, no grain even in 20x24 enlargements. do a google search for either film and you will find quite a few posts about them.