The Autoradiography Ruler Set (ARS) is an orientation and measurement device that exposes metric ruler markings directly onto x-ray film. By means of a specially formulated phosphorescent dye compund and a unique emission filter, the ARS serves as an ideal non-radioactive substitute for radioactive ink markings. The researcher is able to instantly orient the autoradiogram with his/her gel or blot and is thus able to make easy electrophoretic mobility calculations. Since the phosphorescent emission of each ruler can be regenerated indefinitely, it can be reused any number of times. The ARS is a set of rulers made of thin strips of coated plastic with an adhesive backing. The ruler can be affixed temporarily to the gel or blot and then removed for reuse after radiography. In normal lighting the metric units are visible as green markings set against a black background. This special shading technique produces a high resolution image that is unaffected by intensifying screens or preflashed film.