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 Summery.-Illumination
of motion picture sets for black-and-white cinematography involves special
techniques for the long, medium, close-up, and follow shots, as also
the use of booster lights on outdoor sets. Color cinematography requires,
in addition, special attention to the color quality of the light and
the spectral characteristics of the film. The paper includes a discussion
of these requirements and an extensive description of modern lighting
equipment.
When
early motion pictures were made sunlight and skylight were the only sources
of illumination. Glass-covered stages were employed for protection against
the variables of weather. The only means of light-control were reflectors
to re-direct the sunlight, black scrim for diffusion, and opaque mediums
to block out undesired rays.
The
need of auxiliary lighting of a uniform controllable character made itself
evident quite early, and carbon arc lamps, designed for other purposes,
were adapted to studio use. These were largely flame-type flood lamps,
which added to the general illumination but were not capable of light
projection. Later carbon arc searchlights designed for projecting high
levels of illumination into very restricted areas, were introduced.
In these
early days several attempts were made to use incandescent lamps, but the
restricted color-sensitivity of the film then employed and the absence
of high-wattage incandescent bulbs doomed these trials to failure.
The introduction
of panchromatic film and new high-wattage constructions in incandescent
bulbs, coinciding with the introduction of sound, brought about a major
change in motion picture illumination practices.
A desire
on the part of cinematographers for accurate light-control brought the
condenser-type spotlamp, diverging doors, spill rings, special reflectors,
and finally the Fresnel-type lens.
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Fig 1. Large indoor set showing lighting arrangements
for long shot. ( Courtesy Radio Pictures). |
Fresnel-type
spotlamps, introduced with both arc and incandescent sources, have had
wide acceptance. Except for certain special effects this type, where available,
is often used to the exclusion of all others. It furnishes a beam of light
which may be varied, by focusing, to provide the desired illumination
distribution, with beam divergences of 8 to 48 degrees. Depending upon
the size of the equipment, it is used widely for flood-lighting, back-lighting,
cross-lighting and modeling. It is ideally suited for use with special
control devices described elsewhere in this paper. It also facilitates
the use of glass filters necessary in conjunction with CP bulbs to match
sunlight or arc light for color.
BLACK-AND-WHITE PHOTOGRAPHY
Although the spectral energy distributions of unfiltered
carbon arc and incandescent units vary widely, lights from these sources
are
Fig. 2. Medium shot. (Courtesy Warner Bros.)
freely mixed on sets used for black-and-white photography.
Usually the carbon arc is employed where a directional, penetrating source
is required to cut through the general illumination of the set, or where
high levels of illumination are needed on background material, including
streak light, shadow-producing light, sunlight effects, and masculine
characterization.
Incandescent
units are used for broad illumination, and where smallness and lightness
of weight are important, particularly on medium-size sets where high light
levels are not indicated. On small and medium-size sets many cinematographers
use incandescent units,almost to the exclusion of carbon arcs, whereas
others mix arcs and incandescents freely. On large sets most cinematographers
use mixed sources. For close-ups the incandescent is usually indicated
for soft, feminine effects, whereas the arc is often used for masculine
characterization and to produce extreme gradations of illumination.
In the
preliminary arrangement of lighting equipment the chief set electrician,
under the direction of the director of photography, sets in place the
floor and overhead units. The director of photography establishes the
"key-light," which is directional illumination measured near the face
of the principal character, and then rearranges, reduces, or intensifies
the illumination falling upon other areas to achieve the desired balance.
"Balance" is largely an artistic or dramatic rather than a strictly technical
effect.
FIG. 3. Black-and-white close-up. (Courtesy Paramount Pictures)
Although
illumination meters are in common use by cinematographers, the chief set
electrician ordinarily does not use them. His problem is to arrange the
various pieces of equipment, such as lamps, diffusers, dimmers, etc.,
so that the cinematographer may establish a "balance" in a minimum of
time. The placement of this equipment depends upon the experience of the
chief set electrician, his knowledge of the desires of the director of
photography, and the advance conferences that take place before the set
is rigged.
The
Long Shot.-Fig. 1 shows the overhead and part of the floor lighting
equipment for a black-and-white long shot. The lamps are placed high on
parallels around the walls of the set, behind doorways and windows, on
backings, and on the floor in the foreground.
FIG. 4. Follow shot. (Courtesy Warner Bros.)
The Medium Shot.-When the camera equipment is moved in for a medium
shot (Fig. 2) the floor-lighting equipment is moved forward and some of
the overhead lamps are re-directed. Usually no major changes are necessary
in the location of overhead and back-lighting units.
The
Close-Up.-This shot (Fig. 3) is also accomplished by rearrangement
of the front floor-lighting units and the re-direction of overhead lighting
equipment.
Follow
Shot.-On the follow shot (Fig. 4) the camera follows the action around
the set or even from room to room. The technique of lighting for this
kind of shot requires very close cooperation between the director of photography
and the electrical crew. The entire area of travel must be illuminated
properly, and it is often necessary to raise or lower the illumination
levels in certain areas during the actual shooting. This is accomplished
by placing dimmer banks in strategic locations and by cueing the operators
(Figs. 5 and 6).
FIG. 5. Dimmer bank.
Booster-Lights.-On
outdoor daylight shots (Fig. 7) lamps are often used to illuminate important
areas blocked from receiving sunshine or skylight. The action is then
not limited to areas having sufficient natural illumination.
COLOR PHOTOGRAPHY
Color
photography is more exacting than black-and-white photography. The white-flame
carbon arc matches the quality requirements of three-color photography.
The rotating high-intensity arcs and incandescent tungsten sources must
be filtered to provide the required quality. In black-and-white photography
variations of quality and quantity of illumination result only in differences
in shades of gray. In color photography, variation in quality will change
the colors, and low levels of illumination, which in black-and-white photography
result only in obscuring shadows, will often change the appearance of
background, costumes, or features.
Fig. 6. Dimmer bank.
For example, if a colored velvet gown were improperly illuminated
the folds might go black, with the result that the costume would appear
as a colored gown with black stripes.
For this
reason, whereas the illumination meter is used in black-and-white photography
chiefly to establish the "key-light," in color photography it finds wider
use in that both shadow and highlight levels are usually measured. Much
of the equipment arrangements technique that applies to black-and-white
photography applies also to color photography, the major exceptions being
that higher levels are required for color and the quality of the illumination
must closely approximate average sunlight.
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Fig. 7. Black-and-white booster shot.( Courtesy Warner Bros. )
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Fig. 8. Color long shot
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Fig. 9. Color medium shot ( Courtesy Paramount Pictures )
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Fig. 10. Color close-up ( Courtesy Paramount Pictures )
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Fig. 11. Color follow shot
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| Fig. 12. Color booster light shot ( Courtesy 20th-Century Fox ) |
Inasmuch
as the white-flame arc approximates sunlight in quality and a greater
quantity of illumination is available from a single source, the carbon
arc is the most generally used source of illumination for color.
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FIG. 13. Solid line: Spectral energy distribution, 8mm-7-mm MP studio
carbons at 37 volts, 40 amperes. Dotted line: Spectral energy distribution,
solar radiation at sea level.
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| FIG. 14. Photographic effect of light on film. |
The number of incandescent units mixed with carbon arcs
on a color set depends upon the artistic and dramatic requirements from
the viewpoint of the director of photography. Figs. 8, 9, 10, 11, and
12 show the color long shot, medium shot, close-up, follow shot, and booster
light shot.
MODERN CARBON ARC LIGHTING
Modern
developments in both carbons and in lamps have adopted the carbon arc
lighting most effectively to the needs of the studio, particularly for
color photography.
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FIG. 15. Solid line: Spectral energy distribution, 9mm H.I. carbon
arc at 49 volts, 70 amperes-through glass. Dashed line: Same, through
glass and Y-1 filter. Dotted line: Spectral energy distribution, solar
radiation at sea level.
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| FIG. 16. Solid line: Spectral energy distribution, 13.6mm H.I. carbon
arc at 63 volts, 115 amperes-through glass. Dashed line: Same, through
glass and Y-1 filter. Dotted line: Spectral energy distribution, solar
radiation at sea level. |
The radiation through glass from the special motion picture
studio carbons developed for use in broadside lamps resembles sunlight
so closely that it can be mixed with sunlight on color productions without
the use color-correcting filters. The solid line in Fig. 13 shows the
energy distribution so obtained from these carbons and, for comparison,
the energy distribution of solar radiation at corresponding wavelengths.
The peak of radiant energy at about 3900 Angstroms, commonly known as
the "cyanogen band" and usually considered characteristic of the carbon
arc, is suppressed in the radiation from this arc due to the selection
of a relatively low arc voltage. The solar radiation curve is drawn from
data recommended by Parry Moon for use as the standard solar radiation
near sea level. 14
The photographic
effect of a light-source is determined by three factors: intensity of
radiation from the source, transmission of the camera lens, and the sensitivity
of the photographic film.
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| FIG. 17. Solid line: Spectral energy distribution, 16mm H.I. carbon
arc at 81 volts, 150 amperes-through glass. Dashed line: Same, through
glass and Y-1 filter. Dotted line: Spectral energy distribution, solar
radiation at sea level. |
Since each of these characteristics varies with color or
wavelengths, photographic effect is best defined by a curve representing
the products of these three factors at various wavelengths. The photographic
effect of the light from the motion picture studio carbons, previously
mentioned, recorded on panchromatic filmˆ
of the type used in the studios for negative production,
is shown by the curve in Fig. 14. Data for this curve were obtained by
multiplying values of illumination at various wavelengths, as shown in
Fig. 13, by corresponding values of the transmission of the lens and the
sensitivity of the film. The vertical scale of this curve is adjusted
to a maximum of 100.
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Fig. 17(A). (Upper) Typical carbon arc high-intensity rotating element
( Lamps Nos. 4, 5, 6, 7, 8, 9). (Lower) Two views of M-R Type 40 Duarc
broadside carbon arc mechanism ( Lamp No. 3)
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Fig. 17(B). Lamp No. 1: M-R Type 27 scoop. Lamp No.2: M-R Type 29
broadside. Lamp No.3 ( Front and rear views): M-R Type 40 Duarc broadside.
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| Fig 17 (C) Lamp No. 4: M-R Type 65 arc spotlamp. Lamp No. 5: M-R
Type 90 arc spotlamp. Lamp No.6: M-R Type 170 arc spotlamp. Lamp No.8:
36-inch sun arc |
Note that the photographic effect in the red range differs
little from that in the blue.
Radiation
from the high-intensity carbon arcs used for studio lighting is relatively
somewhat stronger in violet and blue components than that from the motion
picture studio carbons. However, a light straw-colored filter (Y-1)4
is sufficient to correct this difference and give substantially the same
spectral balance and photographic effect as obtained from the motion picture
studio carbons. The solid line in Fig. 15 shows the spectral energy distribution
through glass from the 9-mm high-intensity carbon arc at 49 volts and
70 amperes. The dashed curve shows the distribution through glass and
the Y-1 filter. In similar manner, Fig. 16 shows the distribution from
the 13.6-mm high-intensity carbon arc at 63 volts and 115 amperes, and
Fig. 17 the distribution from the 16-mm high-intensity arc at 81 volts
and 150 amperes.
Following
are descriptions of several types of carbon arc lamps now in general use
in motion picture studios.
CARBON ARC LAMPS
Figs.
17(A), (B), and (C) show some of the various types of lamps
in the following list:
(1)
M-R Type 27 Scoop.-Chromium-plated reflector and Factrolite glass
diffuser; solenoid controlled. A twin-arc flood source, used for overhead
illumination of walls, backings, and other areas that can not be lighted
satisfactorily by spotlamps. Suspended singly or in groups. A smooth,
general-purpose light-source.
(2)
M-R Type 29 Broadside.-Chromium-plated reflector and Factrolite glass
diffuser; solenoid controlled. A twin-arc-flood source that may be raised,
lowered, and tilted, and used as a floor-lighting unit for building up
front light to the desired exposure level.
(3)
M-R Type 40 Duarc Broadside.-Chromium-plated reflector and pebbled,
sand-blasted pyrex glass diffuser. An improved motorcontrolled twin-arc
flood-lamp that takes the place of both scoop and broadside of the older
types.
(4)
M-R Type 65 Arc Spotlamp.-Eight-inch diameter Fresnel type lens; high-intensity
rotating mechanism. Used for front and back-lighting, close-up, and medium
shots. The intensity is almost uniform in the main portion of the beam,
tapering off at the edges to permit overlapping adjacent beams without
producing zone of objectionably high intensity. Within its energy capacity
this lamp may be used for all photographic spot lighting.
(5)
M-R Type 90 Arc Spotlamp.-Fourteen-inch diameter Fresnel type lens;
high-intensity rotating mechanism. Used for backlighting, sunlight effects
through doorways or windows, etc., for keylighting on sets of moderate
size, and for general front lighting into the rear areas of deep sets.
(6)
M-R Type 170 Arc Spotlamp.-Twenty-inch diameter Fresnel type lens;
high-intensity rotating mechanism. Used for back, cross, and key lighting,
and for wide and narrow-angle front and effect lighting. This unit has
wider use in both black-and-white and color photography than any of the
other arc units.
(7)
24-Inch Sun Arc.-Twenty-four inch diameter glass mirror; high-intensity
rotating mechanism. Normally used with the arc crater facing the mirror
and a clear glass door on the front of the lamp-house. Where very sharp
shadows are necessary the clear glass door may be moved to the position
normally occupied by the mirror. A metal door is then placed on the open
end. A large number of these lamps have been converted to use the same
optical system as the M-R Type 170 lamp. Used for back-lighting, sunlight
effects through windows and doorways, etc., for key lighting on sets of
moderate size, and for general front lighting into the rear areas of deep
sets.
(8)
36-Inch Sun Arc.-Thirty-six inch diameter glass mirror; high-intensity
rotating mechanism. Similar to the 24-inch Sun Arc except as to size.
The 24-inch Sun Arc is rapidly being converted to the Fresnel type of
lens, but due to its great penetrating power, the 36-inch Sun Arc is valuable
for extremely long throws and retains its popularity in its present form.
When a large quantity of diffused light is required from this unit, a
diverging door composed of strips of cylindrical lenses replaces the plain
glass door. The lamp is used where a very great illumination is required,
as in back-lighting behind a high level of foreground illumination; or
where well defined shadows are required; or where a clearly defined streak
of light is required through the general illumination; or for producing
a general illumination of great penetration and high intensity.
(9)
80-Ampere Rotary Arc Spotlamp.-An 8-inch diameter planoconvex condenser
or 12-inch Fresnel-type lens; high-intensity rotating mechanism; one of
the early high-intensity arc spotlamps. This lamp is not suitable as to
color in its present form because of the spectral energy distribution
of the carbon trim. A number of these lamps have been converted to the
use of 11-mm X 20-inch high-intensity motion picture studio positive carbons
to make them suitable for color photography. They are used for back-lighting
on black and white sets.
INCANDESCENT LAMPS
The incandescent lamp is essentially a piece of tungsten
wire heated to incandescence in a glass bulb filled with an inert gas
to retard the evaporation of the tungsten.
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| FiG. 18. Spectral energy distribution in the visible region from
tungsten filaments of equal wattage but different temperatures. |
The radiation gains in quantity and becomes whiter with
increasing filament temperature. In Fig. 18 each curve indicates the relative
radiant energy throughout the visible spectrum emitted by an incandescent
lamp filament of a given color temperature. Note the values of the upper
and lower curves at the wavelength of 4000 Angstrom units,which is near
the limit of visible light in the violet. The value of the upper curve
at this point is about ten times that of the lower curve. Compare this
with the increase at 7000 Angstroms, near the upper limit of visible red.
Here the upper curve has risen less than three times the, value of the
lower curve.
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FiG. 19. Color-temperature vs. efficiency of Mazda C lamps.
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| FIG. 20. Relative sensitivity of photographic film vs. wavelength
of radiation. |
This fact is important in any photochemical process, since
most photographic materials are more sensitive to radiation in the blue-violet.
The higher the color-temperature of the filament the more photographically
effective is the light.
Fig.
19 shows the increase in efficiency of Mazda C (gas-filled) lamps with
increasing color-temperature, measured in terms of lumens per watt. The
total light output of all incandescent lamps is measured in lumens, and
the data are published in standard lamp catalogs and literature. Fig.
19 therefore provides a handy means of determining the approximate color-temperature
of any lamp by dividing the number of lumens by the wattage. This is of
particular interest to those using other than standard light-sources in
color photography.
In photography we are more interested in the photographic
effectiveness of the light than in its visual effect, and photographic
effectiveness depends upon the type of film used. Fig. 20 shows the curve
of relative sensitivity to radiation at various wavelengths in the visible
spectrum, characteristic of a typical panchromatic motion picture production
negative film.ˆ By multiplying the sensitivity
values given by this curve at various wavelengths by the relative energy
values given by Fig. 18 for the same wavelengths, the family of curves
shown in Fig. 21 is obtained. Fig. 21 provides a picture of the relative
photographic effectiveness throughout the visible spectrum for light-sources
of equal wattage and various color-temperatures for this particular type
of film.ˆˆ Note that
with rising color temperatures the values at the blue-violet end of the
spectrum are increased in greater proportion than those at the red-orange
end. Fig. 22 illustrates the improvement in photographic effectiveness
with lamps of equal wattage, by increasing color temperatures, for the
Panchromatic film in question.
Theoretically,
this increase in photographic efficiency of the light-source is limited
only by the melting point of the tungsten filament at about 3655°K. Practically,
it is necessary to design for an efficiency somewhat below this value,
as the life of the lamp becomes uneconomically short at the extremely
high color temperatures. At present the highest practicable efficiency
is obtained with the photoflood lamps which operate between 3400°K and
3500°K. Therefore, the practical design of an incandescent lamp for photographic
purposes involves a compromise between efficiency, life, size of bulb,
necessary additional equipment, and cost of operation.
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FIG. 21. Relative photographic effectiveness of light-sources of
equal wattage and various color-temperatures.
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| FIG. 22. Relative photographic effectiveness vs. color temperature. |
By designing lamps to operate at high color-temperatures,
high efficiency and good actinic quality are gained. The bulbs can be
comparatively small in size, and the equipment can therefore be relatively
small and easily applied and handled. However, these benefits are gained
at some sacrifice in the life of the light-source. For longer life the
efficiency must be lower and the size of bulbs and equipment larger, or
more equipment must be used for a given photographic value.
As the
wattage of a lamp is increased the tungsten filament becomes thicker and
does not evaporate to the point of failure as quickly,which explains why,
at a given color-temperature, the life of higher-wattage lamps is considerably
longer than for lower-wattage lamps.
FIG. 23. MP and CP lamps listed in Table IV.
For
black-and-white motion picture photography the practice has been to design
the light-sources for a particular length of life, usually between 50
and 100 hours. Such lamps are MP lamps, and are listed in Table IV. Since
they are designed with respect to life, the color-temperatures vary over
a range of approximately 400°K. This results in high-wattage lamps, which
are relatively more efficient and produce higher color temperatures than
the lower wattage lamps.
For color
photography the major consideration is to have light of substantially
the same color-quality from all sources. For this purpose, a second group
of lamps, designated CP lamps, also shown in Table IV, is designed for
a particular color-temperature. Here the higher-wattage lamps have longer
lives than the lower wattage lamps because the heavy filaments do not
evaporate as rapidly. Note that in the case of the 5-kw and the 10-kw
sizes the characteristics of the CP and MP lamps are identical. For this
reason it has become possible to design a single lamp in each of these
two wattages that is correct for both black-and-white and color photography
when operated at the rated voltage. The MP and CP lamps listed in Table
IV and illustrated in Fig. 23, form the backbone of modern studio lighting
practice.
FIG. 24. General service lamps used in broads and floodlights.
They fall logically into four wattage groups, with two
lamps in each group suitable for a particular size of equipment to fill
a specific need. The 10-kw lamp is a possible exception, requiring larger
equipment. This standardization of light-sources and equipment greatly
simplifies the problem of set lighting.
Most
professional color motion picture processes are balanced to a color-quality
approximating that of average daylight. Special color-filters are available
for use with the CP lamps to filter out the proper proportions at the
red-orange end of the spectrum to adapt the light to such processes. If
lower color temperature lamps were used the filter necessarily would have
to absorb greater quantities of red and orange light, and the overall
efficiency would be very low.
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| FIG. 24(A). Lamp No. 10: M-R Type 16 Cinelite. Lamp No. 11: Broadside
(doubles), M-R Type 20. Lamp No. 12: Broadside (singles). Lamp No.
13: M-R Type 45 rifle lamp. Lamp No. 14: Sky light. Lamp No. 15: Overhead
strip light. |
For Technicolor photography, an approved filter, such as
the Whiterlite filter, must be used with the CP lamps.
In many
instances high-efficiency bulbs of the shape and appearance of general
service lamps are used in "broads" and floodlights. Table IV lists the
lamps available for such purposes, and the lamps are illustrated in Fig.
24. The daylight blue photofloods may be used as supplementary light-sources
for color processes balanced to daylight. The smaller lamps in this group
are often used as "practical" lamps, concealed in lighting fixtures and
behind objects on the set. Small standard projection lamps also are often
used in lighting fixtures as "practical" lamps.
Average
Life.-Although a given type of lamp is designed for a particular laboratory
life, obviously they will not all burn out at exactly the same time, but
the majority of them can be expected to fail close to the rated time.
Initial
Lumens.-All lamps are rated according to their initial light output.
The output decreases somewhat throughout life due to blackening of the
bulb by tungsten evaporated from the filament. In gas-filled lamps the
majority of the blackening occurs on the glass directly above the filament,
and is due to currents of gas carrying the tungsten particles upward.
In the 10-kw and 5-kw lamps, considerable blackening may occur in time,
and for this reason a small quantity of granulated tungsten is provided
in the bulb. After approximately each 10 hours of use, the lamps should
be removed from the socket and the tungsten powder swirled about in the
bulb, cleaning off the blackening and restoring the efficiency to nearly
the original value. This tungsten powder is also provided in the 2-kw
T-48 or G-48 mogul bipost MP lamps.
Voltage
Rating.-In general, the photoflood and movieflood lamps are rated
at 105-120 volts. The data on wattage, color-temperature, light output,
and life of these lamps apply to their use at 115 volts. The MP
lamps are usually supplied in the 120-volt class as this is the voltage
available in most studios. However, when the supply lines to the sets
are heavily loaded the voltage is usually closer to 115 volts. For that
reason the CP lamps are ordinarily supplied in the 115-volt class
as it is extremely important that the color-temperature be maintained
at 3380°K. Also at this voltage the color temperature will match that
of the photoflood and movieflood lamps.
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| FIG. 24 (B). Studio spotlamps-lens types. Lamp No. 16: M-R Type
414 senior solarspot. Lamp No. 17: B & M senior. Lamp No. 18: M-R
Type 410 junior solarspot. Lamp No. 19: B & M junior. Lamp No. 20:
M-R Type 406 baby solarspot. Lamp No. 21: B & M baby Keg-Lite. Lamp
No. 22: B & M Dinky Inky. |
A drop of 1 volt below the voltage rating of the lamp will
cause a decrease in color-temperature of approximately 10°K, a decrease
in light output of approximately 3 per cent, and an increase in life of
approximately 6 to 12 per cent.
Following
are descriptions of several types of incandescent lamps now in general
use in motion picture studios.
INCANDESCENT LAMPS
Figs.
24(A), (B), and (C) illustrate the various incandescent lamps described
in the following paragraphs.
(10)
M-R Type 16 Cinelite.-A spun aluminum reflector, finished inside by
wire brushing and chemical treatment, which gives it a diffusing characteristic;
used where lightness and portability are required.
(11)
Broadside (Doubles).-Two flood-type reflectors housed in one unit,
used for floor, side, and overhead lighting. One of the first incandescent
units made.
(12)
Broadside (Singles).-Similar to lamp no. 11, but accommodating only
one bulb.
(13)
M-R Type 45 Rifle Lamp.-Stamped metal reflector, chromium plated with
rifled corrugations for diffusion. Used for general floor lighting.
(14)
Sky Light.-A shallow diffuse reflector about 24 inches in diameter.
Used below and above sky backings and screens, where flat, even light
distribution is required.
(15)
Overhead Strip Lamp.-A trough-like unit containing sockets for five
1000-watt PS52 bulbs. Used to supply fill-in light where it is difficult
to use a more bulky housing.
(16)
M-R Type 414 Senior Solarspot.-A 14-inch diameter Fresnel type lens.
An Alzac spherical mirror is used at the rear of the bulb to direct the
light toward the lens. Used where high-wattage units are desirable, for
back-lighting, front-lighting, and side-lighting.
(17)
B&M Senior.-Similar use to lamp No. 16.
(18)
M-R Type 410 Junior Solarspot.-A 10-inch diameter Fresnel type lens.
An Alzac spherical mirror is used at the rear of the bulb to direct the
light toward the lens. Used for back-lighting, front lighting, and modeling
within its intensity-range.
(19)
B&M Junior.-Similar use to lamp No. 18.
(20)
M-R Type 406 Baby Solarspot.-A 6-inch diameter Fresnel type lens.
An Alzac spherical mirror is used at the rear of the bulb to direct the
light toward the lens. The small size of this lamp permits its use in
places where the larger lamps can not be accommodated, particularly where
it is necessary to conceal a source of high-intensity light.
(21)
B&M Baby Keg-Lite.-Similar use to Lamp No. 20.
(22)
B&M Dinky Inky.-An extremely small Fresnel-type lens unit accommodating
100 or 150-watt bulbs. For use where high-intensity controllable light
is needed at close range from a unit which may be hidden: behind a pillar,
mounted on the camera dolly or carried by an assistant.
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| Fig. 24 (C) Studio spotlamps-reflector types. Lamp No. 23: M-R Type
226 24-inch Sunspot. Lamp No. 24: M-R Type 360 36-inch Sunspot. Lamp
No. 25: M-R Lens Type studio spotlamp. |
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(23)
M-R Type 226 24-Inch Sunspot.-A 24-inch diameter glass mirror, with
a spill ring that allows only projected light to leave the lamp. Used
for back-lighting large sets, in which case the heads are removed from
the pedestals and are mounted on parallels or platforms built at the top
of the set or hung from the stage roof or ceiling.
(24)
M-R Type 360 36-Inch Sunspot.-A 36-inch diameter glass mirror. Used
where the highest intensity of projected light is required from an incandescent
tungsten source.
(25)
B&M Type T-5 and M-R Lens Type Studio Spotlamp.-A short-focus Fresnel-type
lens in front of the bulb and a small fixed spherical mirror behind the
bulb project light forward into the field. This, in combination with the
light projected around the lens from the 24-inch reflector, gives an even,
intense light. For the large mirror, either a 24-inch diameter aplanatic
reflector or a 10-inch focus glass mirror is used. The aplanatic reflector
produces a very even field of light. Greater penetrating power for long
throws may be obtained with the parabolic glass reflector. Used for back-lighting,
cross-lighting, front-lighting, and effect-lighting.
TERMS USED IN STUDIO LIGHTING PRACTICE
The
terms applied to the various units of motion picture studio lighting equipment
are legion and vary from studio to studio, and even from month to month.
Sometimes a lamp is described by its type number alone; or by the rated
current, in the case of arc spotlights; or by the kilowatt rating of incandescent
units. In some instances the mirror diameter supplies the name. Below
are some commonly used terms, the "Lamp Numbers" referring to the preceding
sections:
The
following are a few terms used for material and equipment associated with
the use of studio lamps:
Silks.-Frames
equipped with china silk diffusers, hung on the fronts of lamps to diffuse
the light and reduce the intensity.
Jellies.-Frames
equipped with chemically treated gelatin. Used for the same purposes as
silks.
Scrim.-Black
gauze used in various places to reduce intensity and diffuse light.
Diverging
Doors.-Strips of cylindrical glass lenses. Used on sun arcs for light
diffusion.
Snouts.-Various
shapes of black sheet-metal hangers. Used on the fronts of lamps to block
out undesired light.
Spill
Rings.-A series of sheet-metal tubes, used in front of incandescent
bulbs in mirror-type lamps to block off angular rays emanating from the
front surface of the bulb or filament (see photographs of lamps 23-24).
Spot
Projector.-A unit equipped with a condenser system that fits on the
front of a type 170 carbon arc lamp in place of the Fresnel type lens;
used to produce a sharply defined round spot of light.
Barn
Doors, Gobos, Flags, Cheese Cutters, etc.-It is often desirable to
place opaque screens at various points on a set to keep all or a part
of the light from reaching certain areas or objects. These screens are
painted dull black and are rectangular, square, or circular, as the occasion
may require.
LAMP FILTERS FOR COLOR PHOTOGRAPHY
Carbon
Arc Lamps.-Carbon arc lamps 1, 2, 3 are used for Technicolor photography
without color filters. All types of high-intensity rotating arc lamps
require a type Y-1 straw gelatin filter.4
Incandescent
Bulb Lamps.-Where incandescent bulbs are used on Technicolor photography
a special blue glass Whiterlite filter is required along with a series
of CP-type bulbs, which burn at a uniform color-temperature of 3380°K.11
REFERENCES
(All references are to J. Soc. Mot.
Pict. Eng. except where noted.)
1. MOLE,
P.: "New Developments in Carbon Arc Lighting," XXII (Jan., 1934), p. 51.
2. HANDLEY,
C. W.: "Lighting for Technicolor Motion Pictures," XXV (Nov., 1935), p.
423.
3. RICHARDSON,
E. C.: "Recent Developments in High-Intensity Arc SpotLamps for Motion
Picture Production," XXVIII (Feb., 1937), p. 207.
4. HANDLEY,
C. W.: "The Advanced Technic of Technicolor Lighting," XXIX (Aug., 1937),
p. 169.
5. JOY,
D. B., and DOWNES, A. C.: "Characteristics of High-Intensity Arcs," XIV
(March, 1930), p. 291.
6. JOY,
D. B., BOWDITCH, F. T., and DOWNES, A. C.: "A New White-Flame Carbon Arc
for Photographic Light," XXII (Jan., 1934), p. 58.
7. BOWDITCH,
F. T., and DOWNES, A. C.: "The Photographic Effectiveness of Carbon Arc
Studio Light-Sources," XXV (Nov., 1935), p. 375.
8. BOWDITCH,
F. T., and DOWNES, A. C.: "The Radiant Energy Delivered on Motion Picture
Sets from Carbon Arc Studio Light-Sources," XXV (Nov., 1935), p. 383.
9. BOWDITCH,
F. T., and DOWNES, A. C.: "Spectral Distributions and Color Temperatures
of the Radiant Energy from Carbon Arcs Used in the Motion Picture Industry,"
XXX (April, 1938), p. 400.
10. RICHARDSON,
E. C.: "A Wide-Range Studio Spotlamp for Use with 2000Watt Filament Globes,"
XXVI (Jan., 1936), p. 95.
11. Report
of the Studio Lighting Committee, XXX (March, 1938), p. 294.
12. Report
of the Studio Lighting Committee, XXV (Nov., 1935), p. 432.
13. FARNHAM,
R. E., AND WORSTELL, R. E.: "Color Quality of Light of Incandescent Lamps,"
XXVII(Sept., 1936), p. 260.
14. MOON,
PARRY: "Proposed Standard Solar-Radiation Curves for Engineering Use,"
J. Franklin Inst., 230 (1940), p. 583.
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