Exposure, Image Structure, Storage | Kodak SO-050, 2403 specification

EXPOSURE

Aerial film speeds (ISO A or EAFS) 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 luminances, atmospheric haze conditions, and other factors. Therefore, different film-speed parameters 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.

Nominal speed, daylight (no filter): EAFS or ISO A 500

Other suggested aerial film speeds for processing these films in the KODAK VERSAMAT Film Processor, Models 11 or 1140, using VERSAMAT 885 Chemicals,

641 Chemicals, and Type A Chemicals can be found in the sensitometric data tables.

Note: The aerial film speeds given in this publication were obtained by rounding the calculated values to the nearest cube root of 2 step (equivalent to 1⁄3 stop).

Filters

KODAK PROFESSIONAL WRATTEN Gelatin Filter

	No. 12	No. 25

Filter Factor	1.5	3

Typical Camera Exposure

A typical exposure for this film is approximately 1⁄400 second at f⁄8. This exposure is based on a solar altitude of 5 degrees, a clear day, an aircraft altitude of 5,000 feet, and a speed of ISO A 640 (no filter).

When using an aerial camera equipped with an antivignetting filter, or other filter, it is important to increase this typical exposure by the filter factor of the filter used.

Reciprocity Characteristics

No exposure or development time adjustments are required for exposure times from 1,000 second to 1⁄10 second. At 1⁄10,000 second, increase the development time by 10 percent.

IMAGE STRUCTURE

The following data are based on processing in a KODAK VERSAMAT Film Processor using KODAK VERSAMAT Chemicals.

		Resolving Power		rms
		(line pairs/mm)		rms
		(line pairs/mm)		Granularity*

	TOC 1.6:1		TOC 1000:1
	TOC 1.6:1		TOC 1000:1

VERSAMAT Model 11

885 Chemicals†		40	100	40
641 Chemicals‡		25	100	33
Type A Chemicals§		32	80	55
VERSAMAT Model 1140

885 Chemicals¶		40	100	33

*Granularity values read at a net diffuse density of 1.0 with a

48-micrometre aperture.

†885--2 racks, 10 fpm, 85° F (29.5° C), process gamma 1.40

‡ 641--2 racks, 6.5 fpm, 85° F (29.5° C), process gamma 1.25 § Type A--2 racks, 10 fpm, 90° F (32° C), process gamma 1.70 ¶ 885--1 rack, 15 fpm, 99° F (37° C), process gamma 0.95

STORAGE

For consistent results, all aerial films should be stored under fairly constant conditions. Kodak aerial films are “usually” packaged in equilibrium with 40 to 50 percent relative humidity. High temperatures or high humidity may produce undesirable changes in the film.

Unexposed Film

Store unexposed film in a refrigerator at 55° F (13° C) or lower, or freezer at 0 to -10° F (-18 to -23° C), in the original sealed container. If the film is stored in a refrigerator, remove it about 2 hours before opening; if stored in a freezer, remove it about 8 hours before opening. A sufficient warm-up time is necessary to prevent moisture condensation on cold film— otherwise, moisture spotting, ferrotyping, or sticking may occur.

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).

2	KODAK TRI-X AEROGRAPHIC Film 2403 KODAK TRI-X AERECON Film SO-050 • AS-24