Color Spaces and image quality

When studying the quality of color reproductions we often turn to Color Spaces to help us quantify the difference between two colors. If we know the coordinates of two different samples, we can use the straight-line distance between their positions in three-space as a measure of the color difference or the color error. There are many different spaces, each established with different criteria. Which of the many color spaces is the best? Which mimics human color vision the best? If we want to use a color space to quantify color appearance, the answer is easy. We must use an isotropic color space; that is, one that has the same appearance increments in all directions. Throughout this space a unit of chroma, a unit of lightness and a unit of hue must appear equally different In summary, this paper reviews a variety of color spaces, their criteria and properties. It plots isotropic, observation-based spaces in colorimetric spaces. It discusses which color spaces are consistent with quality issues in pictorial images.