LIGHTING BACKGROUND SURFACES


UP TO this point the acting area and the parts of the
setting immediately surrounding it have been consid-
ered. That part of the stage seen beyond is called "back-
ground" for the sake of convenience. Backgrounds
include entrance and window backings, ground rows,
and the main background in exterior settings. The latter
sometimes surrounds the whole acting area and, partly
due to its area and to its ability to simulate the sky in all its
changes, or to serve as a large canvas on which to paint
with light, the means for lighting it constitutes an impor-
tant item for consideration. Backgrounds should always
be subordinate to the main parts of the setting and to
the actor. They should aim to carry a suggestion of place
and time which stirs the imagination rather than to
delineate sharply. The form and painting of the surface,
particularly if it is to indicate the middle distance and
the far horizon of a landscape in the shallow depth of
the stage, must be carefully considered in relation to the
available means of lighting it. By changing the lighting
it is possible to show the entire course of a day from
noon through sunset, midnight, dawn and back to noon
again without altering the setting itself in any way. The
old painted backdrops with elaborate perspective paint-
in can be lighted by the ordinary borderlights as they

BACKGROUND SURFACES 87

were in the past. But the method for lighting cyclo-
ramas here indicated will tend to give much more even
and controlled illumination and a better stage picture
than is possible with backdrops with Painted perspective.
Door and window backings should be lighted only
enough so that they do not leave black holes in the set-
ting; to convey the atmosphere of the room or space
beyond. Ground rows always tend to appear flat al-
though they are usually painted to represent rolling
expanses of landscape (Figure 2, GR).

CYCLORAMAS
 The early back cloths with painted scenes which were
hung to encircle the rear and the two sides of the acting
area were called cycloramas. Although they are seldom
seen now, there are two general types of modern cyclo-
ramas, smooth and draped curtains, which follow the
same lines as the old ones but are plain in color; and the
solid quarter sphere called a dome or kuppel-horizont.
The draped curtain cyclorama is nothing more than a
large masking piece taking the place of the wings and
backdrop and usually made of rich material either to
take color well or, like black velvet, to absorb it entirely.
The smooth cyclorama (Figure 2, C) is built or hung in
the form of a half-section of a huge cylinder as far from
the acting area as possible to avoid light spill. When used
in this country, the cyclorama is generally painted gray-
blue. In Germany where the stages are generally larger
than ours, two cycloramas that are hung from a curved

88 BACKGROUND SURFACES

track and can be rolled into long vertical cylinders at
each side of the stage, are often used. The one is painted
white so that it will reflect all colors satisfactorily, the
other a dark blue for night skies.
 The dome has a floor plan very much like the cyclo-
rama but it curves forward at the top to mask the flies.
It is found chiefly where the space over the stage is
restricted, and is painted either white or bluish gray.
The modern cyclorama or dome is used most often to
simulate the vast space of the sky in all its variations.
 The chief characteristic of a cloudless sky is its even
tone of blue with its variable but carefully blended color
changes at the horizon line. The surface of the dome or
cyclorama should be free from wrinkles and irregulari-
ties and should be lighted so that the unevennesses
which are unavoidable are least noticed. The design of
settings can be simplified considerably by the use of a
properly lighted dome or cyclorama. If, however, there
is to be an improvement over the old backdrop which
was brightly lighted at the top and bottom and dull in
the center, the scenery should be designed to allow for
the proper placing of instruments which light the cyclo-
rama.
The lighting of both the dome and the cyclorama is
provided by instruments placed at the base and either
near the top or at some distance from and above the
front of the acting area (Figure 2, CL). The instrument

BACKGROUND SURFACES 89

in these, it is possible to run through all the colors of
a sunset. Strips are a great improvement over the large
floods (Figure 20) often laid on the floor to give this
same effect. If the fly space above the stage inside the
cyclorama cannot be cleared, a high-powered strip using
concentrated reflectors can be mounted near the top of
the cyclorama so that its rays are directed down to give
an even illumination over the entire surface. This
method, however, tends to exaggerate any unevenness
in the surface. The best method for lighting the cycle-
raga involves the use of a group of floodlights or several
sections of directing striplights, hung as far down-stage
as possible just out of sight above the acting area to give
a fairly direct throw at the large surface.
 The total wattage per color circuit for the overhead
lights of a cyclorama is, with certain limitations, proper-
tional to the area of the surface lighted. As blue is the
predominant color (and lowest in transmission) for these
lights it requires more wattage than is necessary for the
other colors. If the surface is opaque, less wattage is
required than if it is of dyed cloth, and if painted white,
less than if gray-blue. In order to produce the effect of
a brilliant noonday sky it is wise not to depend upon
dense blue mediums but rather to have a circuit of
medium steel blues or to mix the two other primary
colors with the blue. If the primaries are used they
should be of medium density and not as pure as might
ordinarily be thought necessary. It is wise to allow for


Figure 20: FLOODLIGHTS

A. Olivette floodlight, using 500-1500 Watt pear-Shaped lamps,
with a flat white or aluminum painted reflector.
B. Ordinary ellipsoidal floodlight, using either a 500 or
1000 watt pear-shaped lamp.
C. Small ellipsoidal floodlight using either A-19 100 watt
lamp or a 250-400 G-30 spotlight lamp.

BACKGROUND SURFACES 91

the different percentages of transmission of each primary
and to adjust the circuit wattages accordingly.
  As a basis for the calculation of wattages, 4-8 watts of
blue per square foot of surface to be lighted is recom-
mended. Color mediums differ sufficiently to make it
impossible to state the relation between the transmission
of light by green and red. However, where there are
five watts of blue, red will require three watts and green,
two. These figures can be multiplied by the number of
square feet in the cyclorama area, and then divided by
200, 300, Or 500 (the wattage of each lamp) to deter-
mine the number of individual units needed for each
color. A fourth circuit of white or amber is a practical
addition to give a tint of color instead of depending upon
the other primaries. In practice all colors are of equal
wattage as a rule.
 Instruments hung close to the cyclorama should con-
centrate the rays so that they will project light well up
and down the surface to give even illumination.
 The overhead lights are assisted in lighting the large
surface by the instruments placed at the base. There is
considerable leeway here so that the wattages of the
overhead and base lights should be considered together.
With medium primary color mediums, and efficient
concentrating reflectors in the strips laid at the base,
about 100-200 watts of blue, 75-150 of red, 60-120 of
green and 30-60 watts of white or amber to each running
foot of the base of the dome or cyclorama will provide

92 BACKGROUND SURFACES

adequate illumination to a height of from eight to fifteen
feet. These figures apply to a large cyclorama which has
a linear base measurement between 75 and 100 feet. For
smaller cycloramas they can be reduced proportionally.
The values here given are based on the assumption that
length of the cyclorama base strip (horizon strip or eye
foots as it is often called) is never more than 60% of
the total length of the base line, not only because the
horizon strip follows a shorter radius but also because it
is almost never necessary to illuminate the down-stage
ends of the cyclorama (Figure 1, S). All the wattage
must be included within this shorter length but it is
figured on the basis of the total base line. If the dome or
cyclorama is painted white instead of gray-blue the
figures for the overhead and base lights can be cut almost
in half, but with a white surface, unless the stage is deep,
it is almost impossible to obtain the effect of a midnight
sky when the lighting on the acting area is at all bright,
due to spill, and reflection from the floor cloth.

 In the previous paragraphs it has been indicated that
medium red, green, and blue color should be used in
both the overhead and the horizon lights. However
there are certain limitations to this arrangement. Gener-
ally from overhead it may be wise to use only two cir-
cuits of blue--two units of medium steel to one of
midnight blue. For bright midday the two shades of
blue and amber can be used, but for sunset effects the

      BACKGROUND SURFACES 93

primaries must replace these special colors.
 The distribution of light from the overhead instru-
ments should be even, so that the cyclorama surface
appears evenly lighted. The light from the horizon
strips should blend with the lighting above at an in-
definite height and can fall off at the down-stage ends of
the cyclorama or dome unless absolute realism is desired.
This means that the light must be projected from the
best angle that is practical, both from above and below,
to give complete color mixing and general, shadowless
illumination.
 When an ordinary floodlight is placed close to a large
surface the fall-off of intensity, as the distance from the
instrument increases, is very marked and in order to get
an even distribution either the instrument should be
placed so that it is equidistant from all parts of the
surface, or the reflector must be of such a shape that it
can project the rays to the more distant point to equal
the illumination on the surface close to the instrument.
The beam of light should spread to both sides in a wide
angle when the instrument is close to the surface so that
rays that come from similarly colored units will mix on
the surface close to the instrument. Obviously the hori-
zon strips must be mounted close to the base of the
cyclorama in order to leave the acting area free, but as
much distance between the strips and the cyclorama as is
practical should be allowed. Four feet is many times
better than two feet and the smaller the distance the

94 BACKGROUND SURFACES

smaller must be the spacing between similar colors in
the strip. Sometimes the strip is made in two or three
rows to guarantee good color mixing and to get the
required wattage in the given space. The same conditions
hold for the overhead instruments if they must be
mounted close to the cyclorama.
 When it is possible to sacrifice the space in the flies for
better effect the instruments are hung well down-stage
and away from the surface they illuminate. The problem
of getting good distribution, color mixing, and eliminat-
in irregularities such as wrinkles and seams which show
readily when the light is directed along the surface, is
practically solved when the lights are directed at, rather
than merely parallel to, the surface of the cyclorama.
 The instruments should be medium spread floodlights
(Figure 21) mounted in several rows over the center of
the stage so as to be about equally distant from all parts
of the cyclorama, or they may consist of several rows of
short strips mounted radially in this same position. With
this arrangement a masking border to hide the instru-
ments may be necessary. The height of the border is
determined chiefly by the sight line to the top of the
cyclorama.
 The mounting of the horizon strips is a difficult prob-
lem. If they are mounted in a trap or pit there need be
no masking ground row. The trap should be broad and
deep enough to permit a good color mixing and angle of
throw for the strips. This pit should have trap covers


Figure 21: FLOODLIGHT SECTION

Section through an ellipsoidal floodlight. The heavy lines with
arrows indicate the direction of the rays of light.

(i) Vent space in cap.
(2) Socket.
(3) Pin connector.
(4) Base of lamp.
(5) Color frame slide cover.
(6) Color frame slide.
(7) Pear-shaped lamp.
(8) Filament.
(9) An ellipsoidal, etched aluminum reflector.

96 BACKGROUND SURFACES

which can be closed quickly when the cyclorama is raised
for shifting scenery over it. When the strips are set on
the door they should be mounted on trucks equipped
with casters so that they can be moved quickly; also
a masking ground row is necessary to hide the strips.
With fixed domes and cycloramas the pit with Portable
covers is obviously practical.

The large expanse of a background, such as the cycle-
raga or dome, presents a tempting opportunity for the
technician to "steal the show". Great restraint should
govern the tremendous possibilities of distracting the
audience by an exciting display of color, form, or move-
ment. Even the intensity of the illumination should be
held below the relative values usually given by the sky
bemuse, after all, the actor is the point of emphasis in
the stage picture. Subtlety of balance in the illumination
and in the changes that are included in the course of a
scene is the aim of good control.
 By using the primary colors, particularly in the hori-
zon strips, a satisfactory range of color simulating the
changes of a cloudless sunset can be created. Occasion-
ally just the intensity range of one color is all that is
desired. The German apparatus used overhead (Hori-
zontbeleuchtungsapparat) is so equipped that the color
mediums can be changed over each instrument from the
switchboard. This solves the problem of intensity inas-
much as all the instruments can be made to transmit blue
or any of five different colors that may be desired. Some
BACKGROUND SURFACES 97

American presentation theatres have adopted the practice
of changing color mediums mechanically, bemuse of the
increased amount of light that it gives, but at the same
time color blending is sacrificed so that this system has
its limitations. It is possible to approximate roughly the
variety of effects on the horizon which would occur
when the sun sets or rises at one side of the stage by
controlling the horizon strips in three or more sections,
each color in each section being under separate control.
 The projection of special effects such as clouds and
scenes on the background is considered in another chap-
ter under special instruments, but the German cloud
machine which projects moving clouds on the cyclorama
is practically a standard piece of equipment in every
large European theatre and as such it seems to belong
to the background lighting instruments. Actual pictures
of clouds are projected in the same manner as with the
ordinary lantern slide, and the apparatus is so made that
it can revolve and the clouds can be made to cross, to
rise or to fall at will. The effect tends to be distracting
and will continue to be so until, as with a number of
other things of similar nature in the theatre, it become
commonplace and is accepted. When the background is
used as a surface on which to project any definite form
it loses its depth and tends to become distracting so that
with projected scenery (which some feel is one of the
greatest potential contributions of lighting), great care
must be taken to keep it a related part of the stage
picture.

98 BACKGROUND SURFACES
             GROUND ROWS
 The most expert painting cannot give ground rows
their proper appearance unless the lighting is also well
done. It is difficult to give precise directions concerning
the lighting of this part of the scenery because so many
conditions govern the procedure. However, certain gen-
eral suggestions can be given which will indicate the
right procedure. In the first place the ground row is
ordinarily built like a "flat" with an irregular profile
edge (Figure 2, GR). It is used to represent the middle
distances and the horizon and is generally painted to
represent rolling hills, mountains, or plains. Often
several rows are used to give the sense of greater depth
and perspective. They also serve to mask the horizon
strips if they are high enough, and they should be
designed to allow plenty of space between these strips
and the background. A gauze hung in front of the
ground row tends to throw it into the distance more
than almost anything else. If there are several rows
more than one gauze can be used effectively. Generally
speaking, if the ground rows can be given some form
instead of being flat, it will help to promote plasticity
and they will seem less painted. When the overhead
lighting for the cyclorama is down-stage, above and in
front of the first ground row, this ground row will
receive its general lighting from that source, and it will
appear as a silhouette when only the horizon lights are
used.
BACKGROUND SURFACES 99

 Some overhead cyclorama lighting should be pro-
vided under most conditions because light from below
tends to cast shadows on the background. In front of
each ground row, and two feet or more down-stage, it is
wise to lay a striplight of one color (generally blue, or
three colors if changes are desired) to Promote the sense
of space between ground rows. Strips thus employed
can use 40 watt natural colored lamps because the inten-
sity, unless the ground row is high, should be low. Ordi-
nary backing strips (Figure 22) serve this purpose well.
Occasionally certain parts of the ground rows such as
mountain tops can be picked out, perhaps to show the
effect of the setting sun or to give an added accent. In
this case a small spotlight carefully matted and directed
so that the shadow cast is out of sightline can be used
effectively. Any means of giving ground rows more
depth and form is an advantage.

BACKINGS
 Almost any kind of masking piece that rests on the
stage floor is called a backing. It may be a small back-
drop representing a high wall when seen through the
center door of an interior. It may be a two-leaf screen
(the usual form) serving as a door backing to a side
entrance, a window backing covered with vines or Painted
blue to serve as a small sky piece, or an elaborate off-stage
room with numerous properties. Broadly, even the wings
of the old type of setting might be called backings inas-

100 BACKGROUND SURFACES
much as they set the precedent for lighting this form of
background surface. Usually a backing is just a means
of concealing the back-stage space that might otherwise
be seen by the audience through a door or opening. It
certainly should be unobtrusive and it should be lighted
so that the opening does not appear as a black hole in the
setting. It is practically a rule that all backings must be
lighted so that the actor does not seem to make an en-
trance out of darkness.
 There is no necessity to light the actor specially in
relation to the backing except at the place where the actor
makes an entrance. Strictly speaking the instruments
used to light entrances belong to the special group be-
cause they usually serve as motivating sources. They
must light the actor, and also they are often used to
light the background seen through these entrances.
This section deals primarily with the instruments used
to light the backings alone or in conjunction with special
instruments. The problem is to give a low general dis-
tribution over backing surfaces so that they appear to
belong to the setting proper. Striplights(Figure 14).
using the proper colored lamps mounted above or hung
at the side of an entrance so that the backing is more or
less evenly lighted, and directed so that the actor does
not throw a shadow on the backing surface as he enters,
can serve this purpose. The strip can consist of from
4-12 (depending upon the size of the opening) 25 to 40
watt lamps of selected color to give the general tone. If
it is hung over the door it can be suspended from the
BACKGROUND SURFACES 101

back side of the scenery at least three feet above the
door itself. If hung vertically it should be at least the
same distance down-stage from the door and mounted so
that the bottom of the strip is four or five feet from the
floor.
 Very often it is possible to light a backing with a
floodlight of 100 to 500 watts equipped with the proper
color and a diffusing medium, or projected through a
large diffusing screen. This instrument should always be
mounted well above head height and should be so placed
that the actor will cast as little shadow as possible. Its
position will be close to the setting to get this result.
Where color change is necessary more than one floodlight
must be used or there must be more than one color cir-
cuit in the strip. A window backing can be lighted in
much the same manner as is used for any other backing,
except that here the movement of actors is generally not
involved and the position of the instrument is less crucial.
A little experimenting is necessary to determine the best
position for the backing light after all the parts of the
scenery are in place. Stage braces, which tend to cast
shadows, juts in the scenery, and many other unforeseen
obstacles, require adjustment. The best instrument is
that which gives the most general distribution, and the
best position for it is that which is masked from the view
of the audience and avoids shadows and the quick drop
off in intensity noticed when the instrument is too close
to the surface lighted.