lamp-black n.

c. 1200, "vessel containing flammable liquid and a wick to lift it by capillary action when lit," from Old French lampe "lamp, lights" (12c.), from Latin lampas "a light, torch, flambeau," from Greek lampas "a torch, oil-lamp, beacon-light, light," from lampein "to shine," perhaps from a nasalized form of PIE root *lehp- "to light, glow" (source also of Lithuanian lopė "light," Hittite lappzi "to glow, flash," Old Irish lassar "flame," Welsh llachar "glow").

Replaced Old English leohtfæt "light vessel." From 19c. in reference to gas and later electric lamps. To smell of the lamp "be a product of laborious night study," said disparagingly of a literary work, is attested from 1570s (compare midnight oil). The Greek stem lampad- formed a number of compounds, some in English, such as lampadomancy (1650s) "divination from variations in the flame of a lamp."

Old English blæc "the color black," also "ink," from noun use of black (adj.). It is attested from late 14c. as "dark spot in the pupil of the eye." The meaning "dark-skinned person, African" is from 1620s (perhaps late 13c., and blackamoor is from 1540s). The meaning "black clothing" (especially when worn in mourning) is from c. 1400.

To be in black-and-white, meaning in writing or in print, is from 1650s (white-and-black is from 1590s); the notion is of black characters on white paper. In the visual arts, "with no colors but black and white," it is by 1870 of sketches, 1883 of photographs. To be in the black (1922) is from the accounting practice of recording credits and balances in black ink.

For years it has been a common practice to use red ink instead of black in showing a loss or deficit on corporate books, but not until the heavy losses of 1921 did the contrast in colors come to have a widely understood meaning. [Saturday Evening Post, July 22, 1922]