Well, this will sound really stupid from my side, but... I never understood what that rule means. Yes I know that is one of oldest and firmest rules, but I never used it on purpose. So I would really love if someone explain it to me practically. I belive exposing for shadows means that I measure light in shadows to get details in shadows (or not to have details if I don't want), but what developing for higlights means? For example if I use Ilford ID11 and FP4, at Ilford recommended 8:30 minutes developing time, how practically to use mentioned rule, how and why to change developing time?, les say for portrait, and let say that I use two lights one with f22 and other with f16 and time 1/125 (shooting condition only as example, not real condition, I am interesting in learning how practically to using the rule, not for one time shooting advice asking). Some guidance, please. Thanks.