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Standard observer

The standard observer has been defined in 1931 for the CIE 1931 color model. The standard observer resulted from experiments where observers were asked to match monochromatic wavelengths of light with mixtures of three primary colors (red, green and blue). The standard observer is in fact a table showing how much of each primary color would be used (by an average observer) to match each wavelength of light.

What is a 2 degree standard observer?

In the CIE 1931 color model, the 2 degree standard observer has been defined from color matching experiments with an arrangement that meant that the stimuli activated an area of the retina of 2 degrees. The distribution of rods and cones is not uniform over the surface of the retina and this implies that the tristimulus values obtained from the 1931 data are strictly only valid for observations made under 2 degrees viewing conditions. This is equivalent to viewing a small coin held at arm-length and does not correspond particularly well with the viewing conditions often used in the coloration industry.

What is a 10 degree standard observer?

The CIE 1931 color model was refined and enhanced by a 10 degree standard observer in 1964.