| While slide
duplication is often considered the job of the still
laboratory or photo-finisher, many motion picture
laboratories use the high-volume production techniques
employed in motion picture work to produce slide
duplicates in large quantities. Similarly, filmstrips,
both in 35mm and in small-format sizes such as 16mm,
Super 8mm, and 110 widths, are also frequently handled
by motion picture laboratories. Just
as in the production of motion picture, careful
attention must be paid to the quality of the original
material supplied to the laboratory or slide duplicate
and filmstrip animator. Slides and filmstrips
are produced from both photographic original transparencies
(35mm slides, 4 x 5 sheet film, etc.) and from
artwork or other graphic material. In both cases,
the contrast of the original materials is of extreme
importance in producing best quality originals.
topˆ
Transparencies
There are, unfortunately, no color reversal still
camera films with contrast low enough to be utilized
in the usual duplicating systems employed by motion
picture labs. For this reason, color reversal
still camera films ("chrome films")
require special duplicating techniques to hold
down the contrast.
The photographer of the original
transparencies must keep his subject lighting
as flat as possible, preferably not exceeding
a lighting ratio of 4 to 1. Even with this reduced
lighting ratio, "chrome" transparencies
still require additional contrast reduction for
optimum results. This contrast reduction can best
be applied in the preparation of the master negative
from which the slide duplicates or filmstrip prints
will be made. See Figure 15, page 44.
The best contrast reduction
technique involves the production of black and
white contrast masks from the original transparencies.
This is a costly and time-consuming procedure,
and is therefore used infrequently.
Other methods of lowering the
contrast of the original transparency include
"flashing" the master negative, as is
sometimes done with motion-picture duplicates
from high contrast originals. The success of this
technique depends on the original subject. Since
the effect of flashing is to either lighten the
shadows or darken the highlights (depending on
the kinds of films used and the stage at which
flashing is introduced), in the case of a flashed
negative made from positive transparencies, the
black shadows will be made lighter, or more gray,
which may give the visual impression of lower
contrast in the duplicates.
Some laboratories offer low-contrast
processing of the negative shot from the originals
transparencies. The success of this technique
is also dependent on the subject of the original
photography. It is also possible to use low-contrast
color reversal motion picture camera film for
the original photography. This film is available
in 35mm width but the laboratory must have 35mm
processing facilities for it, and all photography
must be done on the same film to insure a uniform
result in the finished duplicates.
Perhaps the best compromise
between cost and effectiveness that can be used
in making duplicates from high contrast original
photography is the use of a special internegative
film for the duplicating negative. Not all motion
picture laboratories are prepared to handle this
film, although it is commonly used by filmstrip
and slide animators and by labs that specialize
in this kind of work. topˆ
Artwork
Photographing artwork or graphic materials into
slide duplicates or filmstrip offers the opposite
contrast problem from "chrome" original
transparencies. In this case, the contrast of
the artwork is often too low for best reproduction.
The artist should make every effort to keep his
materials as contrasty and saturated as he can.
In the photography of this artwork, polarizing
screens can be used to further enhance the contrast
and saturation. If an entire filmstrip or an entire
set of slide duplicates is to be made from the
artwork then the negative can be photographed
on the same negative film used for motion picture
production, and the contrast will be satisfactory.
However, if original "chrome"
transparencies must be mixed with the artwork
in a single slide set or filmstrip, a single strand
negative will have to compromise either the transparencies
or the artwork depending usually upon which are
most important in the finished duplicates. If
the transparencies are paramount, the artwork
to be intermixed with it can first be copied to
a similar "chrome" film, and then all
of the transparencies of both the original photography
and the artwork can be copied to the special internegative
film described earlier for a uniform result.
Another approach to the mixing
or artwork and transparencies is to photograph
each material in A & B roll fashion on its
own best negative material. This method should
be carefully discussed with the lab as to cost
and technique.
Artwork prepared for slide duplication
or filmstrips should follow the same requirements
as artwork prepared for motion picture animation.
Acetate cels are preferred for overlays, since
polyester cels may exhibit "rainbows"
or "hazing", especially under the polarized
lights used on many copy stands. Pasted up artwork
should be avoided, unless carefully mortised in,
particularly under cels, since the additional
thickness of the paste-up can cause shadows at
the edges. Figure 15 - Flow Chart - Filmstrip
and Slide Production topˆ |
