An infrared color film, Kodak Aerochrome, type 2443, has replaced the 8443 film. The 2443 has lower contrast than the 8443 film, and allows deeper probing into areas that appear as solid black shadows on the 8443 film. The cyan layer of 2443 is approximately 1 1/2 stops slower, at a density of 1.4, than the yellow and magenta emulsion layers

Bowen, R. L.

Cooper, G. R.

Gausman, H. W.

English

NASA Technical Reports Server

// 2 p;~ ~~ D 2 117-1
SECTION 117
THE USE OF KODAK AEROCHROME INFRARED COLOR FILM,
TYPE 2443, AS A REMOTE SENSING TOOL
by @ORMIAL CONRTAM
G. R. Cooper SE b USTRAMS3
Department of Botany
University of Maine
Orono, Maine
and
R. L. Bowen and H. W. Gausman
Soil and Water Conservation Research Division
Agricultural Research Service
U. S. Department of Agriculture
Weslaco, Texas
INTRODUCTION
The use of black and white infrared light sensitive film in "remote
sensing" of natural resources is a relatively recent development. It
was followed closely with the use of Eastman Kodak's false color infra-
red film for camouflage detection (1, 2). The film is well known as
Kodak Ektachrome Infrared Aero, type 84431. It was made available to
interested researchers "over the counter." A new infrared color film,
Kodak Aerochrome, type 2443, has replaced the 8443 film (3, 4), provid-
ing a new horizon and challenge for remote sensing applications with
aerial photography. The 2443 had lower contrast than the 8443 film (3,
4), and allowed the researcher to "probe" deeper into areas that would
have appeared as solid black shadows on the 8443 film. The cyan (infra-
red sensitive) layer of 2443 is approximately 1 1/2 stops slower, at a
density of 1.4, than the yellow and magenta emulsion layers.
1 Use of a company name by the Department does not imply approval or
recommendation of the product to the exclusion of others that may
be suitable.
https://ntrs.nasa.gov/search.jsp?R=19720021760 2020-03-23T08:41:40+00:00Z
117-2
PROCEDURES AND RESULTS
Test procedures applied to the 35 mm Ektachrome Infrared color film
and compared with results for the 70 mm infrared color film indicated
that Eastman Kodak may be marketing two different films. When each was
processed to a negative, the 35 mm film produced a blue base color,
whereas the 70 mm film base color ranged from essentially neutral to a
slight magenta. The data reported here are on the 70 mm film unless
otherwise indicated.
COMPARISON OF 8443 AND 2443 FILMS
Because infrared color prints are needed for publication and as a
tool for field crews doing "ground truth" work, the development of the
new type 2443 Aerochrome Infrared film to a negative was investigated
(5). A panel of research workers was asked to select "the print" they
would prefer to use from both positive and negative transparencies of
the 8443 and 2443 films. Eighty-six percent of the panel indicated a
preference for "the print" made from the negative processing of the 2443
film. A reproduction of the test given the panel is portrayed in Fig. 1.
A general comparison of the old 8443 with the new 2443 infrared
color film indicated that the 2443 film had a lower contrast and some
loss of the vivid coloration that characterized the 8443 film. However,
the 2443 film was superior in yielding details among shadows of plant
canopies whether processed to a positive or negative. The negative
processing, in particular, reveals much more detail in plant canopies
than does the old 8443. This is apparent in the examples portrayed in
Fig. 1.
Quality Control and Analysis of Variance of Density Readings
of Sensitometric Strips Exposed on an EG
and G Mark VI Sensitometer
The quality control of taking and processing photographs was inves-
tigated. An EG and G Mark VI sensitometer (Wratten No. 15 filter) was
used for exposing the film. A Joyce, Loebl microdensitometer was used
to obtain optical density readings of the step wedges printed on the
2443 film. Readings were logged on paper tape for IBM-1800 computer
input and subsequent statistical analyses. The negative processing of
70 mm film allowed 21 steps of the step wedge to be accurately measured
for all three colors, whereas the positive transparency processing would
yield only 19 steps for all colors.
117-3
The analysis of variance shown in Table I was conducted on trans-
formed (log base 10) densitometric data from negative transparencies.
Considering main effects, wedges, steps, and filters had highly signi-
ficant variance (p = 0.01). Significant differences among steps and
filters were expected, but differences among wedges seem undesirable
until consideration is given to their means and the interaction of
wedges with steps. The optical counts for wedges 1, 2, and 3 were 27.2,
27.7, and 27.0, respectively. The interaction of wedges with steps was
not statistically significant, indicating that results were repeatable
regardless of the steps or wedges used.
The statistical significance (p = 0.01) of the interaction of
wedges with filters was mainly caused by the response of wedge 3 with
the white filter. Readings that were lower with this combination are
believed to be in error. The statistical significance (p = 0.01) of
the interaction of filters with steps was expected.
Results, therefore, indicate that repeatable densitometric readings
can be obtained on sensitometric strips exposed on an EG and G Mark VI
sensitometer.
Processing of Kodak Aerochrome, Type 2443,
70 mm Film to a Negative
This processing requires essentially no modification of the normal
C-22 processing to a positive. The film is exposed as it would be for
a positive with no apparent gain or loss of film speed. Two modifica-
tions are: (a) the developer pH is adjusted to pH of 10.6, and
(b) developer time is reduced from 14 to 12 minutes. The result is a
clean, unmasked, color negative that is easy to print.
The film base responds to aging at room temperature to produce a
magenta tint that becomes more intense with increased storage time at
room temperature. Frozen film taken from a freezer, thawed at room
temperature, loaded, exposed, and developed immediately shows an almost
neutral base coloration with only a 0.10 density. Successive develop-
ment of individual sensitometric strips, developed individually in a
Nikor tank and reel, showed the procedure to be reliably reproducible
if temperature, timing, and pH were carefully controlled. Individual
printing equipment varies too much to allow recommendations for initial
filter packs, but a white light print (no filtration, halogen lamp) will
give results that allow an easy assessment of the need for further fil-
tration.
117-4
Processing Kodak Aerochrome Infrared, Type 2443, 70 mm Film
to a Positive in Kodak Ektachrome E-4 Chemistry
This was done according to Eastman Kodak recommendations. However,
pH of the solutions made up from the 1-gallon and 3 1/2-gallon size
packages varied rather widely among lots. Accordingly, the solutions
were adjusted to uniform pH values following recommendations of the
photographic section of NASA at Houston, Texas. The effects of these
variations are still being investigated, and no specific recommenda-
tions will be made at this time.
Other Aspects of Processing Kodak Aerochrome, 2443
The effect of agitation on the E-4 process as applied to 2443 film
appears to be more critical than with S0-397 normal color film in the
same process and should therefore be carefully standardized and watched
for signs of improper agitation.
Research on the storage of 2443 film indicates that film storage
conditions are more critical for 2443 than they were for 8443 film.
Thus, it is necessary to keep the 2443 film refrigerated or actually
frozen for all storage time other than loading, exposing, and
processing.
REFERENCES
1. Applied Infrared Photography. 1968. Kodak Publication No. M-28.
Eastman Kodak Company, Rochester, New York. 96 p.
2. Fritz, N. L. 1967. Optimum methods for using infrared-sensitive
color films. Photogram. Eng. 33:1128-1138.
3. Data Release. 1971. Eastman Kodak Company, Rochester, New York.
5 p.
4. Earth Observations Division Technical Bulletin, 1970. TF6/TB1,
NASA, Manned Spacecraft Center, Houston. 2 p, 4 fig.
5. Pease, R. W. 1969-1970. Color infrared film as negative material.
Remote Sens. Environ. 1:195-198.
117-5
Table I.- Summary table for the analysis of variance for transformed
(log base 10) density readings of sensitometric strips
exposed on an EG and G Mark VI Sensitometer.
Source of variation DF MS
Among runs (R) 1 0.0062
Among wedges (W) 2 0.01140**';
Steps among wedges (S) 18 3.42589**
Among filters (F) 3 2.27717';';
W x F 6 0.00090**
W x S 36 0.00032
F x S 54 0.06694';*
W x F x S 108 0.00025
Error -/ 227 0.00025
Denotes statistical significance, p = 0.01
/- Interactions comprising error
Source of variation DF MS
W x R 2 0.00005
F x R 3 0.00086
W x F x R 6 0.00144
S x R 18 0.00014
W x S x R 36 0.00024
F x S x R 54 0.00035
W x F x S x R 108 0.00014
117-6 
Figure 1.- Representative prints obtained by processing Kodak 
Ektachrome Infrared Aero, type 8443, and Kodak Aerochrome, 
type 2443, films to both positives and negatives. Print A is 
from a positive transparency of 8443, print B is from a negative 
transparency of 8443, print C is from a positive transparency of 
2443, and print D is from a negative transparency of 2443 film. 


The use of Kodak aerochrome infrared color film, type 2443, as a remote sensing tool

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