Often used as the unit for wavelength in the EM spectrum. The quantitative measurement of light level and distribution. A fixture that provides some cutoff, but less than a full-cutoff fixture. A fixture designed to light only a small, well-defined area. The energy output by a source which is of shorter wavelengths than the eye can see.
Some photographic films are sensitive to ultraviolet energy, as are many electronic detectors.
The brightening of the night sky due to manmade lighting. The goal of night lighting. It may be reproduced for non-commercial usage provided that credit is given to IDA .