MOTION PICTURES
Prepared by JR00794
Dec 2021
The Illusion of Motion
Based on empirical studies, individual distinct picture frames
displayed on a screen at the rate of at least 16 picture frames
per second will create an illusion of motion
For commercial motion pictures, the frame rate as projected
on a movie screen was standardized to 24 distinct frames
projected onto a screen per second
Motion Picture Cameras
These cameras expose a series of snap shots on to a
continuous length of photographic film at a rate of 24 shots per
second. The exposed film wound on a reel(s) is developed
similar to conventional photo developing resulting to the motion
picture film that can be projected on to a screen.
The developed ‘snap shots’ are projected sequentially onto a
specially treated screen at a rate of 24 frames per second
creating the illusion of motion using movie projectors.
Motion Picture Projectors
Movies are projected from the developed long strip of film onto
which the individual picture frames (‘snap shots’} were printed
(developed). This strip of film is made to pass through a strong
light source and the resulting images (series of images) are
sequentially projected on a specially treated screen.
Movie Projectors
The motion picture projector pulls the film from a supply reel,
passes the film through a light source and wound around a
take up reel.
A rotating shutter mechanism controls the passage of light thru
the film so that projection is only made when a frame is exactly
positioned in front of the light source
Flickering Effect
The eye is sensitive enough to discern the opening and
closing of the shutter that controls the projection of light onto
the screen. This results to flicker that is strenuous to the eyes
for extended periods
It was found that increasing the shutter speed of projecting
light onto the screen minimizes the flicker effect.
Projectors are designed to project each movie frame twice or
thrice maintaining the standard frame rate of 24 frames/sec
with the shutter opening at a faster rate twice the frame rate
(shutter speed/projection speed)
Soundtrack Offset
§ The sound that accompanies the projected ‘moving’ images
is recorded on the same film strip optically. However, to
prevent the high intensity illumination of the projector from
interfering with the optical pick up of sound, an offset
equivalent to 19-21 frames is implemented in the recording.
During projection, the sound is reproduced through an optical
reader physically away from the main illuminating lamp of the
projector.
TRIVIA
ODEON
Odeon is the name given to several ancient
Roman and Greek buildings where public
performances were conducted
During the late 19th century, the name was
commonly adopted for theaters and later movie
houses.
MOVIE MACHINES
In the early 20th century, coin operated machines
flourished where you drop coins and one can
watch short films on these machines.
MOVIE MACHINES
Each viewing of these short films on the machine
costs a nickel or 5 cents
The machine used to play these short films and
the indoor exhibition space that houses a number
of these machines are then known as . . . .
5 cents = 1 nickel
PROJECTION SCREENS
Early screens are embedded with highly
reflective materials such as aluminum or
silver to enhance the quality of the reflected
‘moving’ images giving rise to the slang term
alluding to the motion picture medium
STAGE LIGHTING
To provide adequate lighting in stage plays before the
advent of electricity, a block of calcium oxide is burned that
in turn emits a bright illumination as the block slowly burns
out.
The common term for calcium oxide is lime.
Hence, the expression . . . .