Candela frequency and that has a radiant intensity in that direction of watt per steradian. The definition describes how to produce a light source that (by definition) emits one candela, but does not specify the luminosity function for weighting radiation at other frequencies. Such a source could then be used to calibrate instruments designed to measure luminous intensity with reference to a specified luminosity function. An appendix to the SI Brochure makes it clear that the luminosity function is not uniquely specified, but must be selected to fully define the candela. The candela is sometimes still called by the old name
Félix Candela enrolled in La Escuela Superior de Arquitectura (Madrid Superior Technical School of Architecture), graduating in 1935; at which time Candela traveled to Germany to further study architecture. Early after he started classes, he developed a very keen sense of geometry and started teaching other students in private lessons. In his junior year, his visual intelligence and his descriptive geometric and trigonometric talent helped him catch the eye of Luis Vegas. Vegas was his material strength professor, and gave Candela the honorary title of “Luis Vegas’ Helper”. While “helping” Vegas, Candela entered many architecture competitions and won most of them. Unlike