as green, and blue reproduces as black (because the film
is exposed through a deep yellow filter). Many other
colors are also formed, depending on the proportions of
green, red, and infrared reflected from the original
scene. Infrared color film was designed for camouflage
detection, and it shows differences in infrared
reflectance between live, healthy vegetation and areas
visually similar, such as pseudo foliage and camouflage
netting. Color IR film should be exposed through a
minus blue (deep yellow) filter, such as a Kodak
Wratten No. 12 or equivalent.
CAUTION
Kodak Ektachrome Infrared film can
not be processed in Process E-6. It must be
processed in Process ME-4, Process EA-5,
or Process E-4. Do not attempt to process
Kodak Ektachrome Infrared film through
any type of E-6 processor. This could
impair the processor and ruin the chemicals.
FILM SPEED
A speed-rating method for aerial film is known as
Aerial Film Speed (AFS). This speed-rating system is
adopted by the American National Standards Institute
(ANSI) and is used to establish the speed of aerial film.
Effective Aerial Film Speed (EAFS) is used to describe
the actual aerial film speed that results from processing
film through any process other than the one specified
by ANSI. Aerial Film Speed and Effective Aerial Film
Speed should not be confused with ISO speed or
exposure index (EI). They are NOT equivalent. When
using ground pictorial films that are assigned an ISO
speed, such as Vericolor, Ektachrome, or Technical Pan,
you should conduct tests to determine which film speed
settings for your camera or light meter will produce
optimum results.
4-16
Figure 4-15.—Aerial photograph taken with black-and-white IR film and a filter.
