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THE EVOLUTION OF THE CARBON ARC LAMP by Richard Twentyman

until being replaced by the carbon arc lamp in the late 19 century,
th
thereby reducing, but not entirely eliminating the likelihood of fires.
The concept of carbon arc lighting was first demonstrated by Sir
Humphrey Davy in the first decade of the 1800s. Davy used charcoal
sticks and an enormous bank of batteries to create a four inch long arc.
With the electrodes mounted horizontally, the strong convection flow of
heated air caused the discharge to form an “arch”. Davy used the term
“arch” lamp, but this was abbreviated to “arc” lamp when this form of
lighting came into common use. The main problem was that, at the time,
the available power sources were of inadequate capacity to sustain the
arc for lengthy durations, and it wasn’t until around 1877 that dynamos
were manufactured which could provide the power necessary to operate
arc lamps for long periods. By the end of the 1800s, these lamps were
being commonly used in factories, parks and for city street lighting. In
particular, arc lamps became the obvious replacement for limelight in
theatrical use.

rom the early days of the magic lantern, to today’s high-tech cinema
Fprojection, light sources have evolved from oil lamps to lasers in
order to achieve the higher and higher lighting levels as required by ever
increasing screen sizes. In 1954, xenon arc lamphouses were
demonstrated at the Photokina in Germany as a viable alternative in those
cinemas using carbon arc lamps. In fact, most European theatres had
converted to xenon arcs long before the rest of the world. In Australia,
many theatres were still using carbon arc lamps as their projection light
source well into the 1990s. In fact, some theatres never converted and
eventually closed with their old carbon arc lamps still operating reliably.
Until the advent of the xenon arc lamp, the carbon arc was the most
commonly used source of light because of its high output and colour
temperature approaching that of natural sunlight.
By 1826, Thomas Drummond had produced a working version of the
limelight, the earliest known public performance under this type of
lighting taking place over Herne Bay Pier, Kent, on 3 October 1836. By
1837, limelight was first used for indoor public performances at the
Covent Garden Theatre in London. Limelight remained as the principal
source of lighting for projectors as well as in live theatre follow spotlights

Top, above and at left: Typical arrangement of low intensity carbon arc as
used for early film projection and in follow spotlights

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