Disclosed herein is an image signal processor for carrying out conversion into an xvYCC signal by using a photograph film as a material, the image signal processor including: acquisition means for acquiring print film concentration data based on said photograph film; generation means for generating spectral data on an image on a screen previously presumed based on spectral concentration characteristics of colors of a positive film having an image projected on said screen, a spectral distribution of a projection light source, and the print film concentration data; arithmetical operation means for arithmetically operating an XYZ tri-stimulus value corresponding to the spectral data; and conversion means for converting the XYZ tri-stimulus value into the xvYCC signal.