Fuji Acros and Kodak TMax 100 are the reciprocity failure champs, that is, exhibit the least failure of any b/w films. The other champs are color negative films, which can go into the hours with no more than 2 stops compensation. Depending on which flavor of Arista.EDU film you're talking about (35mm, large format), the emulsion is coated by Foma, and while it's a beautiful film, it is one of the most reciprocity failure-prone films out there today. +1 stop from 1-10 seconds, +2 stops 10-30, +3 stops after 30 seconds. Although that's nothing compared to Polaroid materials - type 809 was NOT recommended for exposures longer than 1 second, which I can personally verify.