A system for analyzing pressure and/or temperature indicating material has an input for receiving a monochrome color density image captured from a pressure and/or temperature indicating material, the image being captured alongside a calibration target against a contrast sheet. A processing module is configured to receive the captured image of the indicating material and the calibration target and to generate a pseudo colored spectrum map by converting the monochrome color density image into a corresponding multi color map where the different colors on the map correspond to different color densities on the monochrome color density image. The processing module is configured to compare the captured colored calibration target against a stored reference image and to adjust the output pseudo colored spectrum map to account for environmental factors that are present during the capture of the monochrome color density image.