From previous reading, we experienced how RGB representation of the color is used to define different palettes. As it has many different application areas, it has many different schemes.
One representation of the color is HSL. Which corresponds to HUE, SATURATION and LIGHTNESS. It is much easier read and undersand, since it uses our natural way of reading colors. Hue defines the color wheel, which is between 0-360.
More color schematics are defined day by day. For example, in 2011 another color representation called "Cubehelix" is designed specifically for astronomic applications. The problem of using old color schemes can be defined as follow:
Images in astronomy often, but not always, represent the intensity of some source. However, the colour schemes used to display images are not perceived as increasing monotonically in brightness, which does not aid the interpretation of the images. The perceived brightness of red, green and blue are not the same, with green being seen as the brightest, then red, then blue. For example a bright yellow (i.e. full intensity red and green) is perceived as being very much brighter than a bright blue. So if a colour scheme has yellow for intermediate intensities, but blue or red for higher intensities, then the blue or red is perceived at lower brightness. This can be also seen when such colour images are printed in black and white, when increasing intensity in the image does not correspond to a greyscale with monotonically increasing brightness.
The scheme is same components with HSL representatiton but values from HSL is processed with a different function.