Movies for TV - Early Television Foundation

14
FUNDAMENTALS
Thus a standard 400-foot reel of 16 mm film runs for 11 minutes,
and 1000 feet of 35 mm run for the same length of time. An average
length for a newsreel or one-reel cartoon is about 800 or 900 feet.
In the contact printer, many effects are obtained which add to
the atmosphere of the film ; however, in this chapter it is considered
as a printer only. The negative film is run through the gate of this
machine with the unexposed, positive film in close contact with it.
It is, in fact, very similar to making contact prints from the usual
box camera negatives. A variable printing light projects onto
the negative, and this, of course, forms an image on the positive
film, which is opposite in color values when developed. Since the
strength of the light can be controlled, any slight
mistakes in ex-
posure when taking the negatives can be corrected, and because of
the amount of light available a slow positive is used with a very fine
grain. Figure 1-3 shows a standard type of film printer.
Color film is quite complicated in its operation and chemistry.
It will be covered more fully in the chapter on color film and tele-
vision. In brief, there are two general processes, the additive and
the subtractive. In each system the film has to go through a number
of different treatments and in addition to being a long process it
is also costly. While color film as such is of no value to television at
present, owing to the absence of color transmissions, it can be
transmitted quite satisfactorily as a black and white film. The only
precaution to observe is to avoid using film with a lot of blue in it,
such as long shots of landscapes. However, this type of shot is very
rarely used in television films due to the limitations of size and
resolution of the television screen.
Later chapters will deal with the mechanical details of the
equipment used. Therefore, having presented a description of the
medium used to record the images which constitute moving pictures,
it seems appropriate to demonstrate the manner in which these
pictures are given the appearance of moving. The motion picture
film and television both depend for their existence on a phenomenon
known as persistence of vision. This is a "defect" of the human eye
in which the object seen does not immediately vanish from the
retina when the eye is turned away, or the object removed, but the