Blackbody locus

The color of a light source is typacally characterized in terms of its color temperature. If the x,y coordinates of an illumination source do not exactly sit on the blackbody locus, the color of a light source is characterized in terms of its CCT. The CCT is the temperature of a blackbody radiator that has a colour that most closely matches the emission from a non-blackbody radiator. For high quality white light illumination the CCT should between 2500K and 6500 K. There is an accepted method (Wyszelki et al 1982) to determine lines of constant correlated color temperature in x, y space. CIE, CCT and CRI for common white light sources are given in Table 1 for comparison purpose (Misra et al 2006). 

Color from Incandescence. Any object emits light when heated, with the sequence of blackbody colors, black, red, orange, yellow, white, and bluish-white as the temperature increases. The locus of this sequence is shown on a chromaticity diagram in Eigure 14. 

Figure 11.3 is a plot of the spectral blackbody emissive flux as a function of wavelength at various temperatures. From this figure, it is clear that at any given wavelength, the radiative energy emitted by a blackbody increases as the absolute temperature of the body increases. Each curve displays a peak, and the peaks shift toward smaller wavelengths as the temperature rises. The locus of the peaks calculated analytically by Wien s displacement rule is... 

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