A printer includes an image area sensor for picking up a picture frame in photo film to output image data. A printing projecting lens focuses and records a print frame to color photographic paper. Three LED light sources generate light. A digital micromirror device (DMD) is disposed in a traveling path of the light, includes plural micromirrors arranged in at least one array. The plural micromirrors are individually shiftable between first and second positions different in a direction, and when in the first position, direct the light to the photo film by reflection, and when in the second position, direct the light to the printing projecting lens by reflection. A controller initially sets the plural micromirrors in the first position, to illuminate the picture frame in the photo film while the image area sensor is operated. According to the image data, the controller sets micromirrors in one first group in the DMD to the first position, and sets micromirrors in a second group in the DMD to the second position except for the first group, to modulate the light by reflection on the second group. Thus, the print frame is printed with the printing projecting lens.