In figuring your time inputs into the process, if you want to run this as a business don't just figure the amount of time spent in shooting and printing and other obvious time inputs. Think of all your time inputs. I won't try to make an exhaustive list, but it would include all your time inputs, such as meeting with the gallery, ordering your equipment and supplies, working on any marketing or publicity efforts, driving your work to the gallery, billing customers, balancing your business checking account, and all the other time that goes into running your business.