General

On a theater stage, a master switch that extinguishes all stage lights simultaneously.

Uncoated steel pipe, called black  because of the dark-colored iron-oxide scale formed on its surface; usually used for lowpressure

Invisible ultraviolet electromagnetic energy near the visible spectrum; useful for exciting fluorescent paints, dyes, etc., so that they become visible.

A high-quality bituminous paint used as a metal varnish.