Selective yellow is a colour for automotive lamps. Under ECE regulations, headlamps were formerly permitted to be either white or selective yellow—in France, selective yellow was mandatory until 1993.
Both the internationalised European ECE Regulation 19 and North American SAE standard J583 permit selective yellow front fog lamps. ECE Regulation 48 currently requires new vehicles to be equipped with headlamps emitting white light. However, selective yellow headlamps remain permitted throughout Europe on vehicles already so equipped, as well as in non-European locales such as Japan and New Zealand.
The intent of selective yellow is to improve vision by removing short, blue to violet wavelengths from the projected light. These wavelengths are difficult for the human visual system to process properly, and they cause perceived dazzle and glare effects in rain, fog and snow. Removing the blue-violet portion of a lamp's output to obtain selective yellow light can entail filter losses of around 15%, though the effect of this reduction is mitigated or countervailed by the increased visual acuity available with yellow rather than white light in bad weather.
Read more about Selective Yellow: Formal Definition
Famous quotes containing the words selective and/or yellow:
“The selective memory isn’t selective enough.”
—Blake Morrison (b. 1950)
“They are very proper forest houses, the stems of the trees collected together and piled up around a man to keep out wind and rain,—made of living green logs, hanging with moss and lichen, and with the curls and fringes of the yellow birch bark, and dripping with resin, fresh and moist, and redolent of swampy odors, with that sort of vigor and perennialness even about them that toadstools suggest.”
—Henry David Thoreau (1817–1862)