PrintSizer is a darkroom printing calculator that lets you calculate the change in print exposure time when changing the size of the print you are making. It works by being calibrated to the specific characteristics of your enlarger, and then helping you determine necessary time adjustments when your print size changes. To make an enlarger profile more accurate, you can add a set of two test exposures to its profile. These should be height/time combos made on that same enlarger, with the same