The candela (cd), the unit of luminous intensity, is the International System of Units (SI) base unit for photometry — the science of measuring light as perceived by the human eye. The standards ...

A candela has since become “the luminous intensity, in a given direction, of a source that emits monochromatic radiation of frequency 540 x 1012 hertz and that has a radiant intensity in that ...

The measurement of light can be separated into a range of measurement principles. Each of these measurement principles is quantified according to different optical parameters. In the case of ...