Introduction

Geophysical images are, by their nature, intensity images: matrices of real numbers. Thus, representing an image in a color scale will only enlarge the visible dynamic color range without adding any information. But color can be used to encode information taken from a second geophysical image. The combination of the two images produces a meaningful image that can be understood better if two criteria are fulfilled: 1) The information used to create color (referred to from now on as the chrominance image) is entirely separated from the shading (black and white) information (referred to from now on as the luminance image). 2) The frequency content of the chrominance image must be different from that of the luminance image, preferably richer in lower frequencies, since the human eye is less sensitive to high spatial frequency color information. This short note will show how to combine two intensity images (i.e. a seismic section and a velocity model) into a single color image, using the NTSC (National Television Standards Committee) color space.