An optical information recording medium characterized by comprising a temperature-sensitive layer formed on a substrate, for reversibly changing in reflectance andor transmittance with a temperature change. The method includes progressive forming of preheated billets into sculptured dies of corresponding length and width by a forging die of substantially identical width and short length with slightly inclined and flat forging surfaces providing a smoothly convergent working zone, and a periodical transfer of the sculptured die into the working zone between successive strokes of the forging die. Chrominance component values are extracted in various directions of a target sample by using neighboring samples of the target sample.