GE SHOWBIZ - Manual (Page 47)

GE LIGHTING - SHOWBIZ™ ENTERTAINMENT LIGHTING CATALOGUE 88
Typical Working Distance
For Multi-Mirror ® and other reflector lamps and MARC ™ lamps, the Working Distance shown is the
distance from the front surface of the reflector rim to the film plane, in the optical system for which the
lamp was first designed. In most cases, it provides a uniform plane of light for the intended aperture.
Light Centre Length (LCL)
This dimension defines the location of the filament in relation to the lamp base. It is measured from the
geometric centre of the filament to a specified point on, or plane through, the base. Light Centre Length
is subject to manufacturing tolerances.
Maximum Overall Length (MOL)
This dimension includes the lamp bulb and all rigid parts of the base. Since
the listed lengths include maximum tolerances, actual lamps are generally slightly shorter.
GE LIGHTING - SHOWBIZ™ ENTERTAINMENT LIGHTING CATALOGUE 89
Approximate Initial Lumens
The value shown is based on spherical photometry, at rated voltage, of lamps that have been
seasoned for approximately 15% (or a minimum of 2 hours) or more of their rated average life.
Approximate Colour Temperature
The radiation within the visible spectrum from tungsten filament lamps is similar in spectral
distribution to that from a “blackbody” at specific colour temperatures. The Colour Temperatures
shown are approximate initial values in Kelvin (K) for lamps operated at rated voltage.
As the spectral distribution of MARC lamps does not conform to that of a “blackbody”, the values
shown are ‘correlated’ colour temperatures expressed in Kelvin.