KODAK AEROCHROME II Infrared Film 2443
KODAK AEROCHROME II Infrared NP Film SO-134

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Contents

• Description
• Color Formation with Color Infrared Film
  • Normal Color Films
  • Color Infrared-Sensitive Films
• Applications
  • Camouflage Detection
  • Pollution Monitoring
  • Forest Survey
  • Archaeology
  • Ice Reconnaissance
• Base
• Total Film Thickness
• Weight
• Spectral Sensitivity
• Safelight
• Exposure
  • Filters
  • Typical Camera Exposure
  • Reciprocity Characteristics
  • 'Flight-Line Syndrome'
• Image Structure
• Storage
  • Unexposed Film
  • Exposed Film
  • Processed Film
• Processing
  • Chemicals
  • Processing Sequence—5.4 fpm
  • Replenishment and Wash Rates—5.4 fpm
  • Processing Sequence—9 fpm
  • Replenishment and Wash Rates—9 fpm
  • Bleach Regeneration
• Rewind Processing
• Process Control
• Dimensional Stability
  • Temporary Dimensional Changes
  • Permanent Dimensional Changes
• Size Data and Ordering Information
• Graphs

Description

KODAK AEROCHROME II Infrared Film 2443 and KODAK AEROCHROME II Infrared NP Film SO-134 are infrared-sensitive, false-color reversal films intended for various aerial photographic applications where infrared discriminations may yield practical results. These films have medium resolving power and fine grain.

KODAK AEROCHROME II Infrared Film SO-134 is similar in film speed and processing to 2443 Film, but features increased infrared sensitivity. It is particularly suitable for exposures at altitudes above 15,000 feet or where greater infrared response is required.

Both films have an ESTAR Base with good optical properties. The ESTAR Base provides flexibility, moisture resistance, high tear resistance, and excellent dimensional stability.

These films can be processed in Process AR-5 using KODAK EA-5 Chemicals in modern, continuous-processing machines such as the KODAK Aerial Color Processor, Model 1611, or the KODAK EKTACHROME RT Processor, Model 1811. While not a primary recommendation, 2443 and SO-134 can be processed in rewind equipment or on stainless steel reels. However, to offset the different color balances produced by these processing methods, a change in camera filtration is necessary during exposure.

Color Formation with Color Infrared Film

Understanding how color infrared-sensitive films are constructed* and how they develop will assist the user in a better interpretation of the final product. To understand color infrared-sensitive films, some knowledge of normal color films is necessary.

* For further information, see Photogrammetric Engineering, October 1967, Volume 33, pages 1128 to 1138, "Optimum Methods for Using Infrared-Sensitive Color Films," by N.L.Fritz, Eastman Kodak Company.

Normal Color Films

Kodak aerial color films have essentially three photo-sensitive layers. In a normal color film, such as KODAK AEROCHROME II MS Film 2448, the layers are sensitized to the three primary spectral regions—blue, green, and red; during processing, each layer produces a dye of a complementary color—yellow, magenta, and cyan, respectively. The amount of colorant, or dye, produced in any area is inversely related to the intensity of the radiation from the original scene. Thus, each layer is a separate record of the brightness in a single primary color. When visible light is passed through the combinations of the three dyes, a close visual reproduction of the color of the original scene is formed. With a negative-type color film, such as KODAK AEROCOLOR II Negative Film 2445, the colors of the combined dye images will be complementary to those of the original scene.

Color Infrared-Sensitive Films

Any portion of the spectrum to which photographic materials are sensitive can be recorded in a color film if the individual emulsion layer is correspondingly sensitized. Furthermore, the color of the dye formed in a particular layer need bear no relationship to the color of light to which the layer is sensitive. If the relationship is not complementary, the resulting colors are false. False-color films can be used to emphasize differences between objects that are visually quite similar. Color infrared-sensitized films emphasize differences in infrared reflectance. Figure 1 is a simplified diagram that demonstrates graphically how the colors of the terrain are reproduced falsely on color infrared-sensitive films such as KODAK AEROCHROME Infrared Films.

Figure 1: Color Reproduction with KODAK AEROCHROME Infrared Films

As indicated in Figure 1, all three layers are inherently sensitive to blue radiation. Therefore, to limit the exposure of each layer of color infrared film to only its intended spectral region, a yellow filter (minus blue), such as a KODAK WRATTEN Gelatin Filter No. 12 (or equivalent), is always used over the camera lens. It can be seen that with the yellow filter in place, the layers act as though they were sensitive only to green, red, and infrared (as all blue radiation is absorbed by the filter). The grey areas in the top portion of Figure 1 illustrate exposed areas of silver halide in the various layers from each of the spectral bands reflected from the original scene. Thus, three separate negative silver records are formed.

Where there is no exposure, the recommended reversal processing will yield cyan dye in the infrared-sensitive layer, yellow dye in the green-sensitive layer, and magenta dye in the red-sensitive layer. When an image is exposed, the amount of dye formed is inversely proportional to the exposure. The bottom portion of Figure 1 illustrates the dye formation and resulting colors after exposure and processing. Infrared radiation appears as red, which is the result of yellow dye formation in one layer, magenta dye formation in a second layer, and the absence of cyan dye. Green reproduces as blue—the result of cyan dye formation in one layer, magenta dye formation in a second layer, and the absence of yellow dye. Red reproduces as green—the result of cyan dye formation in one layer, yellow dye formation in a second layer, and the absence of magenta dye.

Blue in the original subject has not been recorded because of the filter, and is therefore rendered as black. Numerous other colors will be formed, depending on the proportions of green, red, and infrared reflected or transmitted by the original subject.

Applications

Color infrared-sensitive films (sometimes referred to as "CIR" films) are potentially some of the most useful aerial films currently available to users of aerial photography in a wide range of scientific disciplines. The advantages of color infrared-sensitive films for various applications are well documented in published literature.

AEROCHROME Infrared Films are being used or have been used in agricultural and forest surveys for the detection of crop yields, crop and tree diseases, and insect pests in forests and orchards, as well as in the identification of tree species. For example, changes in infrared reflectance have been used to detect diseased trees in citrus groves and to pick out elms infested by the Dutch elm disease.

Some other applications where color infrared films are being used include: environmental studies, archaeological exploration, surface mining and mined land disturbances, hydrological studies and channel mapping, monitoring oil spills, ice reconnaissance, irrigation studies, and urban mapping where industrial haze exists (the filters used tend to reduce the atmospheric effects). They are also being used in natural resource studies, water pollution studies, instances where geographical and geological changes are in progress, the investigation of erosion along coastal areas, and for discriminating species of coastal marsh land vegetation. Color infrared films are often used in conjunction with black- and-white infrared-sensitive films, natural color films, and other films in aerial multispectral photography.

An indication of how or why color infrared films are being used to extract meaningful information for some of the applications mentioned above is given in the following paragraphs:

Note: A great deal of confusion continues to arise concerning infrared photography and the measurement of infrared energy (heat waves). This confusion often leads to futile attempts to detect thermal patterns through the use of infrared photography in cases where this technique does not apply. Contrary to what many people believe, the infrared record in a photograph is not a measure of ambient temperature variation. Thermal photography cannot be done with infrared-sensitive films because they are not thermal or heat detectors, being only sensitive to the near-infrared spectral region. (AEROCHROME Infrared Films are sensitive to approximately 900 nanometres—see the spectral sensitivity curve in this publication.) Thermal recording usually involves obtaining a visual display of longer wavelength (3 to 5 and 8 to 12 microns) radiation, such as on a cathode-ray tube, and then photographing these thermographic displays by conventional means using standard black-and-white and color films.

A four-page pamphlet, Thermal Recording and Infrared Photography of Hot Objects, KODAK Publication No. P-570, is available. You may obtain a complimentary copy by writing to Aerial Imaging, Eastman Kodak Company, Rochester, New York 14653-7128.

Camouflage Detection

As a matter of history and interest, color infrared-sensitive films were originally designed for reconnaissance and detecting camouflage by aerial photography. The term "CD" was sometimes used to denote the camouflage detection role of these films. Color infrared films were sometimes effective when used to photograph objects painted to imitate foliage. Some paints may have infrared reflectance characteristics quite different than those of foliage. In the resulting color infrared transparency, the areas of healthy deciduous foliage will be magenta or red, and the painted objects may be purple or blue. (However, some paints have now been developed with spectral curves closely approximating those of some foliage.) Camouflaged areas are most easily detected by comparing a transparency made on color infrared-sensitive film with a normal color transparency of the same objects made on KODAK AEROCHROME II MS Film 2448.

Pollution Monitoring

Color infrared aerial films have been used in pollution monitoring applications. These films do not detect thermal pollution such as warm water entering a river from a generating station (see note) or hot gases above a smokestack unless these temperature differences are accompanied by changes in color reflectance or transparency of the water or air. Both water and air when pure have very low reflectance in the infrared. Their reflectance may be greatly increased by the presence of minute quantities of dissolved or suspended materials. Surface "algae blooms" and weeds are recorded as pink swirls; vegetation protruding above the water surface is enhanced by its reddish pink color. Many dissolved chemicals also tend to show up dramatically in color infrared photographs of water bodies. Certain dust, pollens, aerosols, and gases in the air also may be readily detected as well as providing a record of their presence.

Forest Survey

Aerial photographs of foliage made with color infrared-sensitive films often show great variations in infrared reflectivity even when leaves visually show just small variations in shades of green. Although there is a similarity in visual color between deciduous and evergreen trees, healthy deciduous trees have a much higher infrared reflectivity than healthy evergreens. As a result there are significant differences between the colors of these trees as recorded on these films. Also, these color differences are most important in differentiating between healthy and sick specimens. Experienced photointerpreters also take into account the size and shape of the objects as well as color differences when making interpretations. (Shape and size differences are more apparent when stereo pairs are viewed.) Generally, in spring and summer, healthy deciduous trees photograph magenta or red, and healthy evergreens photograph brownish red. Dead or dying deciduous leaves or evergreen needles usually photograph anywhere from dark red to green or even yellow. The leaves of deciduous trees, which turn red or yellow in autumn, still retain some of their infrared reflectivity for a while. Consequently, red leaves may photograph yellow, and yellow leaves may photograph white. In any given vegetation, the season, the water and mineral content of the soil, and the age and health of the vegetation may cause its infrared reflectance to vary. In fact, the first sign of a distressed tree (or plant) is often a decrease in infrared reflectance, which frequently first becomes apparent in color infrared photography.

Archaeology

Color infrared aerial photography is now being more extensively used in this science for the search and discovery of hidden archaeological sites. A change in the color pattern of vegetation detected in the shape or outline of a square, rectangle, or other geometrical pattern has been a clue that something regular and man-made may lie below the earth surface—such as a grave site, building, fortification, or boundary wall. This difference may be easily overlooked in a normal color rendition, and the difference in spectral response might be difficult to separate in a black-and-white rendition.

Ice Reconnaissance

Color infrared film has been used to obtain data on sea-ice distribution and movement. Because of its low reflectance to infrared radiation, water appears very dark and the ice appears light in an image and, therefore, the interface between water and ice and land becomes very discernible.

Base

3.9-mil (0.101 mm) ESTAR Base with a fast-drying backing.

Total Film Thickness

The nominal total thickness (unprocessed) of each film is 4.70 mils (0.12 mm). This includes emulsion—0.80 mil (0.02 mm), base—3.9 mils (0.10 mm), and backing—nil.

Weight

The weight of each film (unprocessed), conditioned in equilibrium with 50 percent relative humidity, is 0.037 lbs/ft² (0.0168 kg/ft²).

Spectral Sensitivity

Color infrared films are sensitive to ultraviolet, visible, and infrared radiation to approximately 900 nm.

Safelight

Total darkness is required for all handling operations such as loading and unloading of camera magazines, and during processing. The base of these films is subject to light piping

Exposure

Aerial Film Speeds (EAFS or ISO A equivalent) should not be confused with conventional film speeds, which are designed for roll and sheet films used in pictorial photography. The characteristics of aerial scenes differ markedly from those of ordinary pictorial or ground scenes because of the smaller range in subject luminance, atmospheric haze conditions, and other factors. Therefore, different film-speed characteristics are used to relate aerial-scene characteristics to practical exposure recommendations.

The KODAK Aerial Exposure Computer, KODAK Publication AS-10, has been published based on the aerial film speed criterion.

Note: The Aerial Film Speed given in this publication is rounded to the nearest cube root of 2 step (equivalent to 1/3 stop).

Filters

A KODAK WRATTEN Filter No. 12 (or equivalent) is required over the camera lens to prevent blue radiation from exposing the inherent blue sensitivities of all three emulsion layers. The spectrophotometric absorption curve for the KODAK WRATTEN Filter No. 12 (deep yellow) (minus blue) is shown in Figure 2.

Figure 2: Spectral Transmission of KODAK WRATTEN Filter No. 12

Typical Camera Exposure

A typical exposure for these films is approximately 1/300 second at f/5.6 with a KODAK WRATTEN Filter No. 12 (deep yellow). This exposure is based on a solar altitude of 40 degrees, a clear day, and an aircraft altitude of 10,000 feet.

Note: If rewind processing or stainless steel reel processing is to be used for processing these films, a filter change for exposing the film is required.

Reciprocity Characteristics

No filter or exposure adjustment is required for exposure times from 1/1,000 second to 1/100 second.

'Flight-Line Syndrome'

KODAK AEROCHROME Infrared Films can be adversely affected by certain environmental conditions, particularly low humidity. Such a drying out can affect the portion of film which dwells on the platen between filght lines or between long exposure cycle times, resulting in a color balance shift. A common practice used to compensate for this effect is to cycle the camera for two frames just before the actual start of the flight line so that all frames are at the same common moisture equilibrium.

Image Structure

The following data are based on processing in KODAK EA-5 Chemicals, Process AR-5.

Storage

Color films, particularly false-color films such as AEROCHROME Infrared Films, are usually more seriously affected by adverse storage conditions than natural color or black-and-white films. Color infrared films are extremely sensitive to variations in temperature and relative humidity. Storage conditions affect the three image-forming layers in different degrees, causing a change in color balance as well as a change in overall film speed and contrast. In the case of AEROCHROME Infrared Films, the infrared-sensitive layer is most affected, causing a loss in infrared sensitivity and a resultant color balance drift toward cyan.

Unexposed Film

The keeping characteristics of unexposed color infrared films are such that they must be kept in a freezer or refrigerator. It is possible to store the unexposed film up to 14 days at temperatures not exceeding 35°F (2°C). Best infrared sensitivity is maintained by storing these films at 0 to -10°F (-18 to -23°C), in their original sealed container. If properly stored at 0°F (-18°C), these films should be removed to room temperature at least 8 hours before opening the container to prevent condensation of atmospheric moisture on the cold film—otherwise, spotting ferrotyping or sticking may occur. The precise time required for warm-up depends on film width, roll length, storage, and ambient conditions.

Exposed Film

Keep exposed film cool and dry. Process the film as soon as possible after exposure to avoid undesirable changes in the latent image. If it is necessary to hold exposed but unprocessed film for several days (such as over a weekend), it should be resealed and refrigerated at 40°F (4°C) or lower. Before unsealing and processing exposed film that has been held in cold storage, follow the warm-up procedures described for unexposed film described above.

Processed Film

For best keeping, store processed film in a dark, dust-free area at 50 to 70°F (10 to 21°C) and 30 to 50 percent relative humidity. Preferably, store negatives on the spool or in individual KODAK Sleeves. High relative humidity promotes the growth of mold and causes ferrotyping. Very low relative humidity causes excessive curl and brittleness. Avoid storage temperatures over 80°F (27°C).

Processing

The primary recommendation for processing KODAK AEROCHROME II Infrared Films is in Process AR-5 using mechanized processors. Mechanized processing in roller-transport processors offers the advantages of uniform treatment of all portions of the roll, freedom from banding, and absence of significant density variations from ends of the roll to the center.

In each case, the film is fed emulsion side down into the processor.

This publication provides general information regarding the KODAK Aerial Color Processor, Model 1611, and the KODAK EKTACHROME RT Processor, Model 1811. Refer to the operating manuals for additional set-up information.

Note: For a list of firms equipped to offer machine processing of 2443 and SO-134 Films, write to Eastman Kodak Company, Aerial Imaging, Rochester, New York 14653-7128.

Chemicals

Process AR-5 uses the following KODAK EA-5 Chemicals:

KODAK EA-5 First Developer *

KODAK EA-5 First Developer Replenisher

KODAK EA-5 First and Second Stop Bath and Replenisher

KODAK EA-5 Color Developer

KODAK EA-5 Color Developer Replenisher

KODAK EA-5 Bleach and Replenisher

KODAK EA-5 Fixer and Replenisher

KODAK EA-5 Stabilizer and Replenisher

* The first developer working solution is prepared by combining one part first developer with two parts first developer replenisher.

Notice: Observe precautionary information on product labels and on the Material Safety Data Sheets.

Processing Sequence—5.4 fpm

Replenishment and Wash Rates—5.4 fpm

Processing Sequence—9 fpm

Replenishment and Wash Rates—9 fpm

Bleach Regeneration

Regeneration of used EA-5 Bleach will reduce processing solution costs and substantially reduce the amount of bleach discarded to the sewer. Collection and treatment tanks for bleach overflow solution and chemical testing capability are required. A detailed laboratory procedure is available from Eastman Kodak Company.

Rewind Processing

Note: This is not a primary recommendation.

KODAK AEROCHROME II Infrared Film 2443 and KODAK AEROCHROME II Infrared NP Film SO-134 yield optimum results with modern, high-temperature, continuous-processing machines. They can be processed in rewind equipment or on spiral reels, although these methods are not a primary processing recommendation. Eastman Kodak Company no longer offers packaged chemicals for such processing. Customers wishing to use rewind equipment such as the Gordon/Morse M-10 Developing Outfit (Military Designator: B-5) may contact Aerial Imaging for information on exposure, processing chemicals, process cycles, and general recommendations.

Process Control

Processing fluctuations should be kept to a minimum. Follow the recommended procedures and include process control strips at regular intervals. KODAK Control Strips, Process AR-5, are available and are recommended for monitoring the processing of AEROCHROME II Infrared Films and several other color aerial films in Kodak roller-transport processors using EA-5 chemicals. For detailed information on process control and trouble-shooting, refer to "Using Processes AR-5 and AN-5 for KODAK Color Aerial Films," KODAK Publication Z-200.

Dimensional Stability

The dimensional stability of aerial films is of particular interest and importance in accurate mapping and in the reproduction of maps.

Dimensional stability is an all-inclusive term. In photography, it applies to size changes caused by changes in humidity and in temperature, and by processing and aging. The absence of solvent in ESTAR Base is one of the reasons why ESTAR Base films show excellent dimensional stability. The dimensional properties of ESTAR Base may vary slightly in different directions within a sheet; the differences that may exist, however, are not always between the length and width directions.

Temporary Dimensional Changes

Permanent Dimensional Changes

Size Data and Ordering Information

KODAK AEROCHROME II Infrared Film 2443 is available in sizes for certain aerial cameras. The following factory-stocked sizes are available without minimum-order requirements:

KODAK AEROCHROME II Infrared NP Film SO-134 is factory-stocked in the following size without minimum-order requirements:

Information on minimum order quantities by size of this film is available by writing or calling:

Aerial Imaging

Eastman Kodak Company

Rochester, New York 14653-7128

253-1855

Note: The Kodak materials described in this publication used with KODAK AEROCHROME II Infrared Film 2443 and KODAK AEROCHROME II Infrared NP Film SO-134 are available from those dealers normally supplying Kodak products. Other materials may be used, but equivalent results may not be obtained.

Graphs

These graphs are designed to be printed in landscape mode. They will print properly on most printers in their current page set-up of 100%. However, some printers may require adjustments to the browser page set-up in order to have the graph print on a single 8 1/2 x 11 inch sheet of paper.

Modulation Transfer Function

Characteristic

Spectral Sensitivity

Spectral Dye Density

Note: The contents of this publication are subject to change without notice.

Note: The contents of this publication are subject to change without notice.

Kodak, Aerochrome, Aerocolor Estar, Ektachrome, and Wratten are trademarks.

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Footnotes\Notices

TI2161 • Revised 9-00