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Toggle the table of contents. Orders of magnitude (illuminance) ... Bright sunlight 120 kilolux: ... Fluorescent lamp [5] [6] 10 5:
The Sun closely approximates a black-body radiator. The effective temperature, defined by the total radiative power per square unit, is 5772 K. [12] The color temperature of sunlight above the atmosphere is about 5900 K. [13] The Sun may appear red, orange, yellow, or white from Earth, depending on its position in the sky.
Illuminants A, B, and C were introduced in 1931, with the intention of respectively representing average incandescent light, direct sunlight, and average daylight. Illuminants D (1967) represent variations of daylight, illuminant E is the equal-energy illuminant, while illuminants F (2004) represent fluorescent lamps of various composition.
Table of comparative luminous flux of several light sources [7] [8] [9] Source Luminous flux (lumens) 37 mW "Superbright" white LED: 0.20 15 mW green laser (532 nm wavelength) 8.4 1 W high-output white LED: 25–120 Kerosene lantern: 100 40 W incandescent lamp at 230 volts: 325 7 W high-output white LED: 450 6 W COB filament LED lamp: 600 18 W ...
The two major innovations of the unit were the high-frequency ballast, which gave the lights greater intensity and eliminated flicker commonly found in off-the-shelf fluorescent tubes, and the Kino Flo tubes, which contained a number of special phosphors designed to eliminate the characteristic tints in the magenta-green spectrum which are present in most domestic fluorescent lights. [3]
Researchers use daylight as the benchmark to which to compare color rendering of electric lights. In 1948, daylight was described as the ideal source of illumination for good color rendering because "it (daylight) displays (1) a great variety of colors, (2) makes it easy to distinguish slight shades of color, and (3) the colors of objects around us obviously look natural".
Full-spectrum light is light that covers the electromagnetic spectrum from infrared to near-ultraviolet, or all wavelengths that are useful to plant or animal life; in particular, sunlight is considered full spectrum, even though the solar spectral distribution reaching Earth changes with time of day, latitude, and atmospheric conditions.
As such, they are very inefficient, because most of the radiant energy they emit is invisible infrared. A compact fluorescent lamp can provide light comparable to a 60 watt incandescent while consuming as little as 15 watts of electricity. The lumen is the photometric unit of light output.