Hue, Intensity, Brightness

The Hue (or simply, the "colour") is the dominant Wavelength or dominant frequency

Energy distribution of a light source with a dominant frequency near the red end of the frequency range

• The integration of the energy for all the visible wavelengths is proportional to the intensity of the colour

• Intensity : Radiant Energy emitted per unit of time, per unit solid angle, and per unit projected area of the source (related to the luminance of the source)

• Brightness : perceived intensity of light