Abstract: A method and apparatus are provided for producing a color thermogram on a color film beginning with images, such as those of a black and white television monitor, projected on the color film through color filters, with preferably three achromatic images being formed. The intensity of the achromatic color in each image as a function of temperature is selected in accordance with a predetermined characteristic or relationship and the images are projected through a color filter having a separate color for each image, e.g., blue, yellow and red. In this way the same portions of the image with achromatic colors which conform to the characteristic selected for the different filters are projected through the different filters, so as to produce a picture having color hues which vary between the colors of the filters. For example, a green hue is produced for an "overlap" of the characteristics for blue and yellow.