Color temperature is the expression of energy levels of light sources in Kelvins (K), based on the notion of a perfect absorber which changes color dependent on the temperature it is heated to. Lower color temperature ratings correspond to the emission of more yellow light, whereas higher color temperature ratings are associated with a more […]
A spectral power distribution (SPD) is a graph of the energy levels of a light source through a range of wavelengths of light. The spectral power distribution is the true “fingerprint” of a light source, as it is the key to how the light source renders colors. The image below shows the SPD of an […]
ISO 3664 defines Chromaticity as the “property of a color stimulus defined by its chromaticity coordinates, or by its dominant or complementary wavelength and purity taken together.” The apparent color of a light source, specified by its three chromaticity coordinates. Since the human eye has three types of color sensors that respond to different ranges […]
Color viewing, even near the D50 standard color temperature, is only as accurate as the quality of the light source. The CRI, or color rendering index, is a quantitative scale which measures the quality of color shown by a light source. This is based on how colors appear to the human eye and how clearly […]
Metamerism exists when two materials match under some lighting conditions but not under other lighting conditions. It is the occurrence of colors which have different properties appearing to match under a particular light source, yet under other light sources they appear to mismatch. This can be a serious problem for manufacturers. If you combine different […]