LRGB, short for Luminance, Red, Green and Blue, is a photographic technique used in amateur astronomy for producing good quality color photographs by combining a high-quality black-and-white image with a lower-quality color image. [1]
In astrophotography, it is easier and cheaper to obtain good quality, high signal-to-noise ratio images in black and white. The LRGB method is used to work around this to get good color images. The color ( chrominance) information from the color image is combined with the overall brightness from the black-and-white image.
The theory behind the effectiveness behind LRGB techniques has been related to the working of human color vision. [3] The rod cells in human eyes are sensitive to luminance and spatial data, while the cone cells are sensitive to color. There are three types of cones: those sensitive to red, those sensitive to green, and those sensitive to blue. Thus, each element of LRGB targets one type of photoreceptor cell in the human eye.