Abstract: In a photothermographic laser imaging system including a laser printer for exposing photothermographic media to digital data, a thermal processor for thermally developing the exposed media to render a visual image of the digital data, and a densitometer for reading the density of the visual image; a method for maintaining calibration of the system comprising the steps of: exposing by means of the laser printer successful photothermographic media with digital data and simultaneously with the digital data, density patches on an edge of the media representing minimum density, D.sub.min, and mid density, D.sub.mid ; reading with the densitometer the D.sub.min and D.sub.mid density patches of successive media developed by the thermal processor for a predetermined number of media or over a predetermined interval; averaging the read D.sub.min and D.sub.mid values to obtain average D.sub.min and D.sub.mid values; comparing the averaged D.sub.min and D.sub.mid values with preferred D.sub.min and D.sub.