In my day-job I design training, and I'm working on a photography-related piece right now. I'm trying to determine the best way of controlling what a learner sees on his/her computer screen regarding the brightness of an image. Overall, it seems as though the only practical way to address this (within the context of a course, that is) is to have the learners adjust their monitors using something like Adobe Gamma, either the real Gamma or some in-house, home-grown version thereof. My question is, how accurate is gamma? Will it hit within, say, half a stop across the learner population, assuming that they perform the process properly? Are there other, similar solutions (i.e., solutions which don't require anything more than the monitor and the user) which perform better?