Mel Frank, “When We Were Criminals,” at M + B Photo. Back in the ’70s, Mel Frank helped write the literal book on how to grow pot: the 1978 manual “Marijuana Growers’ Guide Deluxe.” He also took a lot of pictures — of the harvest, of plants, of buds, of the botanical processes necessary to cultivate cannabis. This exhibition is the first to bring together the work of this California botanist, writer and photographer whose cannabis cultivation guides served as bibles of weed way before there were such things as private equity firms focused on cannabis. Through June 9. 1050 N. Cahuenga Blvd., Hollywood, www.mbphoto.com.