Although the floppy disks used in electronic imagery are not light sensitive, they are, however, a commonly used image-recording medium. All floppy disks are the same. There are no black-and-white and color floppy disks. The camera and the printer being used determine whether the image is black and white or color. Images are stored as magnetic impulses on compact 2-inch still-video floppy disks.

The pictures are recorded on tracks on a still-video floppy disk. Each picture is recorded either as a FRAME or FIELD (the frame or field mode is selected on the camera). When the frame mode is selected, each picture is recorded on two tracks. Twenty-five images can be recorded on a floppy disk in the frame mode. When the field mode is selected, each picture is recorded on one track In the field mode, 50 images can be stored on each disk. The result of using one track per photograph is the images are less detailed than those recorded on two tracks (frame mode). The quality of the frame-recorded image is superior to that of the field-recorded photograph. A combination of field and frame images can be stored on the same disk; however, for higher quality use the frame mode.

Sound can also be recorded on a floppy disk. Sound is not recorded on the same track as the image. It is recorded right after the image is recorded. The sound associated with the picture can be heard during playback

Floppy disks used in electronic imaging can be reused for endless times-the same as any other magnetic recording medium. No chemicals or darkroom techniques are required to produce these images. Once the image is captured on the floppy disk, it can be transmitted over the telephone lines, edited, and printed using a video printer-all under normal room-lighting conditions.

BLACK-AND-WHITE PRINTING PAPER

The performance and use of black-and-white photographic printing paper, like black-and-white films, depends on the characteristics of the paper material. While the many types of photographic papers differ in their characteristics, they all basically consist of the emulsion on a paper support or base. Photographic printing papers (both black and white and color) are manufactured in both various cut sheet sizes, ranging from 5x7 to 20x24 inches and rolls up to 1,000 feet long.

Photographic papers used in Navy imaging facilities are either coated with polyethylene or are resin-coated. These papers are coated on both sides of the base. This clear coating is treated so the paper does not stick to the surface of other prints during processing. Polyethylene-coated papers (manufactured by Ilford) can be marked on with pencils and pens. Coated papers have water-resistant bases that provide short processing times. Most black-and-white papers with these coatings have developing agents incorporated in the emulsion. The developing agents are activated when the paper is exposed to an alkali solution. The characteristics of resin-coated paper make it ideal for machine processing, but they may also be tray-developed in a regular print developer.

The image on black-and-white film is usually negative or recorded in tones of gray in reverse of the reflective brightness values of a scene. When the negative image is projected onto black-and-white paper, the resulting image is positive or recorded in tones of gray relative to the reflective brightness values of the original scene. A negative is usually used or viewed by transmitted light. A paper print (or simply a print) is usually viewed by reflected light and may be referred to as a reflection print or reflection positive.