Basically, you don't. Your best bet is to use high speed film and either use a wide angle lens or stand back from the subject, then enlarge a lot. But with enlargement, you also lose some definition in the picture. Another possibility is to scan the negative and use one or more of the available filters for Photoshop to get a more or less equivalent effect. Just about any color film you can get these days has very fine grain, and when you do see it, it looks mushy, not sharp. From my little experience with them, Fuji films seem to have somewhat sharper grain than Kodak films.