An optical method of pseudocolor equidensity encoding of photographic image is described. Frequency modulating of input image is made through! a four grey-levels halftone screen and the pseudocolor encoding is performed in a spatial filtering system where the white light source is used with the color filter placing at the plane of the source slit. The halftone screen is made by means of the Talbot eifect which incorporates the equivalent of low-pass spatial filtering. The spatial frequency of the screen is up to 12.51p/mm. The one-dimensional space-banswidth product is up to 750. The remote sensing image processed by using this method is available.