were reconstituted according to the schematic in Figure 6. The
spectral response of photographs similar to Kodak Aerochrome MS,
Type 2448 (a color positive film) for example, can be simulated by
reproducing a black and white film positive from each of the blue,
green, and red multispectral negatives (steps 1 and 2, Figure 6,.
The blue, green, and red positives are then projected on the viewing
screen through the appropriate filters, i.e., the blue image through
the blue filter, etc., (step 3, Figure 6). Similarly, the response
of Kodak Infrared Aerographic film (Type 2424, black and white IR)
exposed through a red No. 25 Wratten filter can be simulated by super-
imposition of the red and IR multiband images on the viewer Screen
without filtration. With the four multispectral images in the viewer,
the image interpreter can simulate the response of a large number of
film and film/filter combinations by selecting the proper viewer
channels and filtration (Table 2).
TABLE 2. SPECTRAL BANDWIDTH OF STANDARD FILM,
FILM/FILTER COMBINATIONS AND EQUIVALENT MULTISPECTRAL CHANNELS
Resultant Multispectral
Standard Sensitivity Filter Spectral Channels
Film Type Range (nm) Cut-Off (nm) Range (nm) Required
Plus X 350-700 Yellow (15) 500-700 Green, Red
Aerographic 500
Type 2402
Infrared 350-900 Red (25) 580-900 Red, IR
Aerographic 580
Type 2424
Aerochrome MS 400-700 Clear (UV) 400-700 Blue, Green,
Type 2448 400 Red
Aerochrome 400-850 Yellow (15) 500-850 Green, Red,
Infrared 500 IR
Type 2443
Discussion
Certainly color aerial photography is not needed in every phase
of a course designed to train image interpreters in the art of ob-
taining information from photography. In the commercial world, most
demands for photogrammetric measurements can be met by cartographic
or metric quality panchromatic photography. Similarly, objects or
terrain features that can be detected and identified from either their
physical characteristics, location, or their contextural relationships
to other features do not require color photography. Species of vege-
tation, soil type, soil moisture relationships, and certain rock
