Theatre Design & Technology - Oct 1972 - 19

from 75 to 90% of the light they receive. These filters are
very light in color, mostly oranges and yellows and produce a whitish light toned according to an identifiable
color. Group II, pastel colors transmit 60 to 75%. These
appear more definitely a given color and do so because
they are relatively more pure than the colors of Group I.
Group III, the rich colors are not useful for lighting the
acting area, but are excellent accent colors. Ranging from
40 to 60% transmission, these colors transmit light of sufficient intensity to be seen clearly. Group IV, the dark
colors transmit up to 40% of the light they receive. Those
of the very lowest percentages, mostly in the greens and in

observer, the color differences of the Bastard Ambers fall
into three groups. Brigham ;;:02, Cinemoid #52, Gelatran
#16 and Rosco .:':'902 constitute a group that is orange
tending toward yellow, whereas Rosco .:':'203 and 802 tend
toward red. In the middle of these two is the group including Cinemoid =51 and Rosco .:!202. Numbers have
been employed above because similar colors identified by
the name Bastard Amber are not consistently employed.
Brigham uses the term Light Scarlet, Cinemoid uses Pale
Gold and Gold Tint.

the blues, may not be useful at all.

without undue color alteration. Ideally, a neutral reducer
should absorb equal amounts of all wavelengths of energy.
The spectrophotometric curve for the grays should, therefore, be a straight line. However, the grays have dominant
wavelengths which fall in the violet and blue ranges of the
visible spectrum. As a result, more of the warm colors are

V
Finally, a colorimetric study involves the identification
of a color sample by its dominant wavelength. The dominant wavelength is the wavelength that is dominant in the
color. It expresses numerically the hue sensation the color
possesses by establishing it at some point in the visible
spectrum. For each sample, establish the position of the
dominant wavelength in relation to the spectral colors.
This is especially valuable when the eye cannot aid in
determining a specific hue. For example, observe a swatch
of Brigham Gelatine ;;:02, Light Scarlet. Is it red or is it
orange? Reference to its dominant wavelength reveals that
the figure 591.0 mu falls within the orange range, 590-610
mu.
Dominant wavelength can be observed graphically by
relating it to the illuminant point on the chromaticity
diagram. A straight line is struck off from IIluminant A
through the point locating a specific color and to the
perimeter of the chromaticity diagram, from which the
dominant wavelength can be directly read. The dominant
wavelength for Brigham i'f45, Blue-Green could be
matched by a mixture of IIluminant A and spectral light
having a wavelength of 499.3 mu. The blue-green is aptly
named for 499.3 mu falls within the blue-green range,
490-500 mu.
For the unreal colors, the dominant wavelengths are
given for their complements. Brigham #6, Rose Pink for
example, is identified by the dominant wavelength of its
complementary color, 492.7 mu (Cl a green ish-blue spectral wavelength. The symbol C identifies the wavelength as
being that of the complementary color.
Some of the most useful colors vary enough among
brands to warrant attention. Special lavender is perhaps
the most widely employed, particularly in conjunction
with Bastard ,Ll.mber. Cinemoid ~36, Pale Lavender with a
dominant wavelength of 467.9 mu has a decided purple
hue sensation whereas the others, Brigham =17 and Rosco
=242,841,842,942 and 943 appear a blue purple, Only
Gelatran -=t80 falls in the violet range with a dominant
wavelength of 442.1 mu. Note their placement in the special lavender cluster shown in Figure 5.
While the effect would go unnoticed even by a trained

THEATRE DESIGN AND TECHNOLOGY

Chocolate may be considered by some as the equivalent to gray in application, a means of reducing intensity

absorbed than the cool. The chocolates are not as consistent. Three colors, Rosco #882, #982 and, to some extent, Cinemoid #56 have a brownish-gray quality that
make them as useful as the grays for reducing intensity.
These have dominant wavelengths in the yellow area of
the visible spectrum. Brigham ';::-69 and Rosco #282 are
about the same in dominant wavelength located in the
magenta-purples, but differ in saturation. An excellent
choice for an 3cting area warm color is Brigham #70, the
richest of the chocolates. It has no grayish-brown cast to
it; its domi nant wavelength - 567.4 mu is in the green
range toward the yellow side.
Of the cool colors, the blues are available in such variety that color selection is difficult. Furthermore, it is very
difficult to determine whether a sample is a true blue, a
green blue or a violet blue. The eye is of less help here
since it is less sensitive to this range of color. Once again,
comparison of the dominant wavelength provides clarity.
Since one buys a fairly large supply of blues to keep in
stock, it would be sensible to arrange the blues by dominant wavelength and per cent of transmission and select
from a cross section (figure 7).
Certain warm colors are not desirable for use in lighting
the acting area because of the presence of noticeable
amounts of green. Many of the yellows are particularly
notorious in this respect. While a single beam of greenishyellow light projected from above or to one side of the
acting area could serve to identify locale, the objection to
a green cast on the face is undeniable. Few yellow filters
transmit amounts of green small enough to pass unnoticed, although the straws are workable. When selecting
yellows refer to Figure 8. Colors with dominant wavelengths of 575 mu contain noticeable amounts of green
and progressively more as the numbers go down.
VI
Samples in this appendix have been placed in associational color categories according to their dominant wavelength. Brand names are listed alphabetically.

OCTOBER. 1972

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