luminance

Photometric counterpart of radiance, producing the visual sensation called brightness. Typical units are: $candela m −2$ ( $nit$ ), $candela cm −2$ ( $stilb$ ), $foot lambert$ ( $2.426 nit$ ). As with all photometric quantities, luminance does not refer to a specific wavelength, but applies to light emitted by a standard source (formerly a 'standard international candle', now a blackbody radiator emitting at the temperature of solidifying platinum, $2042 K$ ). Conversion from photometric units to radiometric units (e.g. $J s −1$ ) requires convolution over wavelength of the relative spectral response of the human eye (photopic response tables).

Source:

PAC, 1990, 62, 2167 (Glossary of atmospheric chemistry terms (Recommendations 1990)) on page 2199