Movies for TV - Early Television Foundation

176 FUNDAMENTALS
and magenta, absorb red and green respectively, while yellow
absorbs blue. Therefore, on projection, the reversed film provides
its own filter system to reproduce the colors correctly.
Du Pont
Du Pont has now entered the field with a color release positive j
film. It is not intended for use in cameras but only for making
prints from three black and white negatives of the color separation
type. It is a standard, integral tripack film, but it differs from
others on the market in that the emulsion color layers contain only
two components silver halide and a synthetic polymer which is
water-sensitive. The latter takes the places of the gelatin as well
as the color former. The new color former is insoluble in water,
and the polymer prevents contamination of other colors by it. The
layer arrangement is different from standard practice,
the color-
sensitive layers being placed as follows, descending from the sur-
face to the base:
Emulsion Sensitivity Polymer Color
Blue Magneta
Red Cyan
Green Yellow
Film Base It will be noted that the yellow layer is on the bottom
instead of the top. This is possible since printing is done on
a registration printer and whichever color master film is desired
can be directed to the proper layer by machine adjustment. It is
interesting to note that this system is based on the fact that yellow
is the least important color as far as definition is concerned, and
the diffraction and diffusion effects produced by the passage of
light through two layers are of no importance.
A point of interest to the sound engineer is that the layer ar-
rangement makes it possible to use a blue-sensitive photo-electric
cell in the sound head with a dyed sound track. This improves
both volume and quality.
If daylight film, which has been balanced chemically for daylight,
is exposed by artificial light, the correction which may be