Kodak's film data sheets are the best source for technical information about KODAK and EASTMAN Motion Picture Films. Each data sheet consists of one or more pages of detailed technical information for a particular film. These sheets provide useful information for the careful and knowledgeable reader.

In the discussion of professional motion picture films that follows, we are using that form of a Film Data Sheet as a road map. The next four pages illustrate a data sheet for a hypothetical film that can be used in every stage of motion picture work. A real data sheet would obviously have fewer entries--camera film data sheet, for example, does not contain paragraphs titled "Printing Conditions" because printing conditions are only relevant to laboratory and print films.

The large circles on the hypothetical data sheet illustration that is shown on the next few pages contain page numbers referring you to the beginning of a discussion on that specific topic. For example, the data sheet has a (4) on the section "exposure indexes." If you scroll down and find the(4) and the heading "Exposure Index," you can read about that topic. Each number on the data sheet will refer you to that section in the text.

A single free copy of any film data sheet is available from Eastman Kodak Company, Dept. 412-L, Rochester, NY 14650-0532.

Film Types, Names, and Numbers(1) and (2)
Film production-from recording motion with a camera to projecting the image on a screen or cathode-ray tube-often involves three different kinds of film.

Camera film is used to record the original scene. Many kinds of camera films are available for the many conditions under which subjects often must be filmed, for the special effects the cinematographer wants to produce, and for the processing and projection requirements of the job.

Once the film has been edited from a workprint, laboratory films used to produce the intermediate stages needed in the lab for special effects, titling, etc. Using intermediates also protects your valuable, original footage from potential damage during the printing process.

Print film, on the other hand, is used to print both the first workprint and as many copies as needed of the final edited version of the project.

People in the photographic industry generally refer to films by number (5248, for example) rather than by name (EASTMAN Color Negative II Film, in this case). Thus, the four-digit number is more prominently displayed on the film data sheet than the name. The first of the four digits indicates the size or "gauge" of the film. When the first digit is 5, the film is 35 mm or wider; a 7, on the other hand, indicates a 16 mm film or a film that will be slit down to these narrower gauges after processing. When a film is available in both the 16 mm and 35 mm widths, both the 7000 and 5000 series of digits appear on the data sheet.

	Motion Picture and Television Products Division EASTMAN KODAK COMPANY POCHESTER, NY 14650
EASTMAN Color Print Film 5200 and 7200 KODAK Publication No. H-1-5200	Kodak, Eastman, and Wratten are trademarks.	Minor Revision 9-90-B Printed in U.S.A.

The name also indicates properties of the film. KODAK EKTACHROME Film indicates a reversal color film. Panchromatic and orthochromatic refer to the light-sensitivity range of the film. Most film names are self- descriptive.

The important thing to remember about the name and number is to use both accurately when ordering film or film data sheets.

Film Descriptions(3)
Under the heading General Properties on a typical data sheet, there will always be a brief description of the overall characteristics of the film. The paragraphs that follow describe each of the KODAK and EASTMAN Motion Picture Films currently available and are similar in coverage to paragraphs found on each film data sheet.

Negative Camera Films
Camera films are available in two general types: negative and reversal. Negative film produces an image that must be printed on another stock for final viewing. Since at least one intermediate stage is usually produced to protect the original footage, negative camera film is an efficient choice when significant editing and special effects are planned. Printing techniques for negative-positive film systems are very sophisticated and highly flexible; hence, negative flim is especially appropriate for complex special effects. All negative films can go through several print generations without pronounced contrast buildup.

Exposure Information
Film data sheets for camera films give exposure information under these headings: Film Exposure Indexes, Illumination Table, Lighting Contrast Ratios, Reciprocity Characteristics, and Filter Factors (black-and-white film) or Color Balance (color films). Explanations of each of these elements are explained on the following few pages.

Exposure Index(4)
The film Exposure Index (EI) is a measurement of film speed that can be used with an exposure meter to determine the aperture needed for specific lighting condifions. The indexes reported on film data sheets for EASTMAN and KODAK Motion Picture Films are based on practical picture tests but make allowance for some normal variations in equipment and film that will be used for the production. There are many variables for a single exposure. Individual cameras, lights, and meters are all different (lenses are often calibrated in T-stops). Coatings on lenses affect the amount of light that strikes the emulsion. The actual shutter speeds and f-numbers of a camera and those marked on it sometimes differ. Particular film emulsions have unique properties. Camera techniques can also affect exposure. All of these variables can combine to make a real difference between the recommended exposure and the optimum exposure for specific conditions and equipment. Therefore, you should test several combinations of camera, film, and equipment to find the exposures that produce the best results. Data sheet Exposure Index figures are applicable to meters marked for ISO speeds and are used as a starting point for an exposure series.

When it comes to measuring light, there are three kinds of exposure meters: The averaging reflection meter and the reflection spot meter are most useful for daylight exposures while the incident exposure meter is designed for indoor work with incandescent illuminations. Detailed directions for using all three are given in KODAK Pocket Photoguide, KODAK Publication No. AR-21). The two reflection meters are sometimes used with the KODAK Gray Card. One side of the card has a neutral 18-percent reflection which can be used indoors to aid in measuring the average reflection for a typical subject. You can also use this side of the card outdoors by increasing the exposure 1/2 stop above the calculated exposure. The other side of the card has 90-percent reflection for use at low- light levels. The use of this card and appropriate adjustments for aperture and exposure time is covered in KODAK Gray Cards, KODAK Publication No. R-27.

Exposure Latitude
Exposure latitude is the range between overexposure and underexposure within which a film will still produce usable images. As the luminance ratio (the range from black to white) decreases, the exposure latitude increases. For example, on overcast days the range from darkest to lightest narrows, increases the apparent exposure latitude. On the other hand, the exposure latitude decreases when the film is recording subjects with high-luminance ratios such as black trees against a sunlit, snowy field.

Illumination (Incident Light) Table (5)
When the illumination is very low or when you cannot make reflected-light measurements conveniently, use an incident-light meter can be used to read the illumination direcdy in footcandies (lux).

Note: Lux is the term used to describe the intensity of the exposing light in the current international standards for determining film speed. Most existing incident-light meter scales are still marked in footcandles. A footcandle is approximately equal to 1/10 metre-candle or lux.

Lighting Contrast Ratios(6)
When using artificial light sources to illuminate a subject, you can determine a ratio between the relative intensity of the key light and the fill lights. First, measure the intensity of light at the subject under both the key and fill lighting. Then measure the intensity of the fill light alone. The ratio of the intensities of the combined key light and fill lights to the fill light alone, measured at the subjects, is known as the lighting ratio.

Except for dramatic or special effects, the generally accepted ratio for color photography is 2 to I or 3 to 1. If duplicate prints of the camera film are needed, the ratio should seldom exceed 3 to 1. For example, if the combined main light and fill light on a scene produce a meter reading of 6000 footcandles at the highlight areas and 1000 footcandles in the shadow areas, the ratio is 6 to 1. The shadow areas should be illuminated to give a reading of at least 2000 and preferably 3000 footcandles to bring the lighting ratio within the permissible range.

Lighting contrast ratio 2:1	Lighting contrast ratio 5:1
Figure 1

Reciprocity Characteristics(7)
Reciprocity refers to the relationship between light intensity (illuminance) and exposure time with respect to the total amount of exposure received by the film. According to "The Reciprocity Law," the amount of exposure (H) received by the film equals the illuminance (E) of the light striking the film multiplied by the exposure time (t). In practice, any film has its maximum sensitivity at a particular exposure (i.e., normal exposure at the film's rated exposure index). This sensitivity varies with the exposure time and illumination level. This variation is called "reciprocity effect." Within a reasonable range of illumination levels and exposure times, the film produces a good image. At extreme illumination levels or exposure times, the effective sensitivity of the film is lowered, so that predicted increases in exposure time to compensate for low illumination or increases in illumination to compensate for short exposure time fail to produce adequate exposure. This condition is called "Reciprocity Law Failure" because the Reciprocity Law fails to describe the film sensitivity at very fast and very slow exposures. The Reciprocity Law usually applies quite well for exposure times of 1/5 second to 1/000 second for black-and-white films. Above and below these speeds, black-and-white films are subject to reciprocity failure but their wide exposure latitude usually compensates for the effective loss of film speed. When the law does not hold, the symptoms are underexposure and change in contrast. For color films, the photographer  must compensate for both film speed and color balance changes because the speed change may be different for each of the three emulsion layers. However, contrast changes cannot be compensated for or contrast mismatch can occur.

Filter Factors(8)
Since a filter absorbs part of the light that would otherwise fall on the film, you must increase the exposure when you use a filter. The filter factor is the multiple by which an exposure is increased for a specific filter with a particular film. This factor depends principally upon the absorption characteristics of the filter, the spectral sensitivity of the film emulsion, and the spectral composition of the light falling on the subject.

Published filter factors apply strictly to the specific lighting conditions under which the measurements were made, so it may be desirable, especially for scientific and technical applications using reversal films, to determine the appropriate filter factor under actual working conditions.

To determine a filter factor, place a subject with a neutral-gray area, a KODAK Gray Card, or a photographic gray scale in the scene to be photographed. Shoot the scene without filtration. Then, with the filter or filter pack in place, shoot a series of exposures at 1/2-stop intervals ranging from 2 stops under to 2 stops over the exposure determined using the published filter factor. Compare the (neutral-gray) density of one frame in the unfiltered scene with the density of one frame in each one of the filter series, either visually or with a densitometer to find the filtered exposure that equals the unfiltered exposure in overall density. The filter factor is the ratio of the filtered exposure to the unfiltered exposure with equal densities.

Color Balance(9)
CoIor balance relates to the color of a light source that a color film is designed to record without additional filtration. All laboratory and print films are balanced for the tungsten light sources used in printers, while camera films are nominally balanced for 5500 K daylight, 3200 K tungsten, or 3400 K tungsten exposure.

When filming under light sources different from those recommended, filtration over the carnera lens or over the light source is required. Camera film data sheets contain starting-point filter recommendations for the most common lighting sources: daylight, 3200 K tungsten, 3400 K tungsten, cool- white fluorescent, deluxe cool-white fluorescent, and Mole-Richardson HI Arc lamps (both white-flame and yellow-flame carbons).

Printing Conditions(10)
A representative printer setup is described for each laboratory or print film. These printer setups should be read for comparison purposes and used only as a starting point. The use of the Laboratory Aim Density (LAD) control method is recommended for determining optimum printing exposure.