We use Optical Character Recognition (OCR) during our scanning and processing workflow to make the content of each page searchable. You can view the automatically generated text below as well as copy and paste individual pieces of text to quote in your own work.
Text recognition is never 100% accurate. Many parts of the scanned page may not be reflected in the OCR text output, including: images, page layout, certain fonts or handwriting.
42 III. 16-MM FILM AND ITS CHAEACTEEISTICS
Original Film Materials (1) Reversal film (black-and-white) for original photographing. (I?) Color reversal for original photographing.
(3) Positive-type dyed film for variable-area sound originals.
(4) Negative film for special purposes (rarely used commercially).
Duplicating Film Materials
(5) Dupe negative — fine grain.
(6) Master (dupe) positive — fine grain.
Release Print Materials
(7) Black-and-white release positive — fine grain.
(8) Color-reversal print stock.
(9) Reversal (black-and-white) print stock.
Original Film Materials
(1) Black-and-White Reversal Film
"Reversal film is a film which after exposure is processed to produce a positive image on the same film rather than the customary negative image. If exposure is made by printing from a negative, a negative image is produced directly."
Reversal films may be either panchromatic black-and-white or color, and either sound or silent, and they are usually 16-mm and narrower in width. As currently manufactured, most reversal films are of high contrast suited to projection.
As has already been mentioned, the film used in the 16-mm camera is customarily a reversal film. Like most other modern film for picture taking, black-and-white reversal film is usually made in two or more emulsion layers. The top layer usually has higher speed (and coarser grain) than the layer below it; this layer arrangement materially improves the exposure latitude. Figure 1A is a photomicrograph of the cross section of a modern two-layer film.
Reversal film is given reversal processing.* The film first enters a developer bath where the larger emulsion grains are developed, being most sensitive to light. The film next enters a bleach bath that bleaches out the larger film grains just developed, leaving the remainder of the film unaffected. The film is next given a second exposure or "fogging" over its entire surface, exposing the finer emulsion grains that were unaffected by either the original exposure and by the first developer. The film next enters a second developer bath in which the finer emulsion grains are developed and produce the blacks of the final image that appears on the film.
* Reversal processing is described more completely in Chapter XII.