A method for determining a position of a mechanical edge of a reference edge of a sheet of recording media relative to a first edge of a drum slot in a cylindrical surface of an imaging drum, the method includes mounting the sheet of recording media on the imaging drum in an orientation wherein the reference edge extends along the cylindrical surface of the imaging drum in a substantially axial direction and wherein the reference edge extends over the first edge of the drum slot; establishing at least one acute apex diffuse light source in the slot; capturing at least one digital camera image of the reference edge and the at least one acute apex diffuse light source; and determining from the at least one digital camera image a location of at least one point on the mechanical edge.