Klieg light
A Klieg
light is
an intense carbon arc
lamp especially
used in filmmaking.
It is named after inventor John
H. Kliegl and
his brother Anton
Tiberius Kliegl.
Modern Klieg lights use a tungsten-halogenfilament.
They usually have a fresnel
lenswith
a spherical reflector or an ellipsoidal reflector with a
lens train containing two Plano Convex lens or
a single step lens.

Film
The carbon-arc source was so bright that it allowed film directors to make
"day" at night, which also heralded the era of blinding actors – a term
coined as "Klieg eye".
Stage
In the early days of spotlights, the name "Klieg light" became synonymous
with any ellipsoidal reflector spotlight, another carbon-arc source or any
bright source. Initially developed for film, the Klieg light was adapted
to an incandescent stage
fixture in 1911.
Although not completely certain, the title of the first ERS (Ellipsoidal
Reflector Spotlight), often goes to the 1933 Klieglight,
which was first used to light an outdoor pageant in New York. Century
Lighting introduced their Lekolite developed
by Levy & Kook, hence the "Leko", in the same year.
The Universal Electric Stage Lighting Company, Kliegl Bros. Props. was
founded in 1896 and grew to be the largest stage lighting company in the
world. The company closed in the 1990s.