The Polaroid SX 70 Sonar camera has been modified so that it will produce instant photographs of the fluorescence of fluorescein in illuminated rooms. The camera was used to record the dye pattern in 40 rats and 65 patients. The photographic method proved to be as good as--but no better than--the visual one in predicting the viability of skin flaps. The camera eliminates the need to totally darken the room and use an ultraviolet lamp; it provides useful information to the surgeon and a permanent record for the chart.