Theatre Design & Technology - Oct 1973 - 17

SPECTROPHOTOMETRIC COMPARISONS OF
THE EFFECTS OF STAGE LIGHTING ON
NEWLY DEVELOPED EXPENDABLE
COLOR MEDIA
TONY COURTADE

STATE UNIVERSITY COLLEGE, CORTLAND, N. Y.

INTRODUCTION
The importance of the use of color to the stage lighting
designer as an artistic variable in the creation of stage
lighting is without question. Yet the types of color media
used in the realization of that creation present a real
problem, for the stability of the different types of color
media becomes a critical factor in maintaining a consistent
color balance throughout rehearsal and performance
periods. A valuable experiment in the durability of five
different marketed brands of gelatine and plastic color
media was done by Gary W. Gaiser and Minor Rootes at
Indiana University (see Theatre Design and Technology,
May, 1967, pp. 5-20). Obvious extensions of this study
include an examination of all available colors, but even
more important is an expansion of the study to include
the newer products now available. The experiment represented by this current study is a continuation of the work
done by Gaiser and Rootes focussing on recently marketed
polyester and mylar products of expandable color media.
The significance of this study evolves directly from the
experiments in the transmission of spectral energy of color
media done by Gaiser and Rootes in a series of tests dOle
in 1958, 1961, and 1964 on Brigham and Roscogel gelatines and Cinabex, Cinemoid, and Roscolene plastics.
The current study involves Roscolar and Gelatran. The
procedure and a certain amount of the expectation of
results of the current research are based on that earlier
study.
At the very basis of this type of study is the actual
rate of color fading (often called burnout) which affects
the spectral transmission of any color medium. After the
medium has been exposed in front of a lighting instrument
for so long a period of time that the color no longer
transmits the appropriate visual properties, and therefore
represents a different response in terms of audience
psychophysics,l then the color of the medium becomes
unacceptable and it must be replaced. For that reason
there is a need to ascertain the exact time at which the
color has faded to the point where it no longer serves its

THEATRE DESIGN AND TECHNOLOGY

purpose. Often a visual examination of the medium itself
will not confirm whether the color output has changed.
Therefore, an examination of spectral transmission is
necessary.
This study, and the Gaiser-Rootes study of which It IS
a replication, endeavours to test specific marketed brands
of color medium under conditions wh ich are not atypical
of stage practice. By the testing of colors representative
of much of the color spectrum, and also of colors which
are popular in terms of use, this study hopes to establish
a pattern of burnout in the specific color areas chosen, to
show the relationship of burnout patterns in the specific
brands of media chosen for testing, and to relate that
data to the media and color areas tested by Gaiser and
Rootes. This study seeks to evaluate the effects of typical
stagelighting on the duration of color in the media
examined. This approach provides enough standardization
to allow comparison and evaluation. While the more
rigorous "laboratory" methods are not approximated, this
evaluation of empirical results comes close to actual stage
lighting practice.
The color areas chosen were five: pale blue, primary or
medium blue, bastard amber, golden or medium amber,
and lavender (often called special lavender or surprise
pink). These areas were chosen for their apparent representation of color ranges within the visible spectrum.
Primary blue has high radiant energy in the blue portion
of the spectrum and in no other portions except in the
longest red wavelengths. Amber transmits little or no
energy in the violet, blue and green areas, and depends on
high radiant energy in the yellow, orange, and red areas.
Lavender transmits highly in the red and blue areas, but is
much lower in the center of the spectrum. The two less
saturated colors, pale blue and bastard amber, represent
high levels of transmission in most areas of the spectrum,
but reach their highest levels at opposite ends of the
spectrum. I n addition to the representative spectral range
covered, the bastard amber, pale blue, and lavender are
colors having a high incidence of use in lighting practice.

OCTOBER. 1973

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