Carbon arc
[Film Technology]
A luminant created by a gaseous discharge
between two cerium-cored carbon rods. These carbon trims burn for a limited duration (e.g. 45
to 90 minutes) where arc lamp produce high intensity
light of excellent colour quality and sharpness, they require skilled operation and
maintenance to achieve these properties, and to sustain an even, constant light out-put. Mainly used as high intensity light sources for large-area or exterior lighting.
Available in 225 amp (brute) down to smaller fresnel spot and follow
spotlight versions (65amp) 6000/335 0k, 1/2-1 hour burning time. Carbon arcs are low voltage, high
current sources developed in motion picture studios
to provide high intensity light of excellent colour quality. The arc being a very concentrated
point source, produce very sharp, crisp illumination
with enhanced modeling lighting, texture, textural lighting
and shadow formation ; with the advent of other
powerful, more compact, and less demanding light
sources, the use of carbon arcs has lasted in both film studio and
television studios. Arc lamps require a DC
supply (usually 115v). The gaseous arc itself
is drawn between two cerium-cored white-flame carbon
rods or trims. These continually burn away, the motor driven feed
rotating the positive pole to sustain a symmetrical crater. Burning life is
limited to about 90 minutes, plus the need for cool-down
time before redimming. Carbon trims burn
at colour temperatures from around 6000-3350 K,
depending on their core material; corrective colour
filters being used to adjust or match their light as required. A
luminent created by a gaseous discharge between two cerium-cored carbon rods.
The trims [Carbon
trims]burn for a limited duration
( e.g. 45 to 90 minuets) while arc lamps
produce high intensity light of excellent
colour quality and sharpness, they require
skilled operation and maintenance to achieve these properties, and to sustain
an even, constant light out-put.
