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Proposed American Standard
16mm Motion Picture Projector
For Use With Monochrome Television Film
Chains Operating on Full-Storage Basis
(Fourth Draft)
PH22.91
1. Scope
1.1 This standard applies only to 16mm motion picture projectors in which the film is advanced intermittently.
1.2 Projectors complying with this standard can be used only with film chains which operate on a full-storage basis.
1.2.1 In full-storage operation illumination from the projector is restricted to the vertical retrace period of the television scan.
1.3 Many of the characteristics of the projector cannot be standardized in specific terms unless the pickup tube used in the film chain is specified. Since the Type 1 850-A iconoscope is used almost exclusively at present jn filmchain equipment, it has been used as the basis of standardization. If the projector is to be used with any other type of pickup tube, it will be necessary to modify the following paragraphs of this Proposed Standard: 2.1, 2.2, 3.1, 3.2.1, 8.1 and all subparagraphs.
2. Image Dimensions
2.1 An image width of 4!/2 inches shall be considered standard. (See Paragraph 1.3.)
2.2 The range of focus adjustment shall be sufficient to accommodate widths of image from 3% inches to 5 inches. (See Paragraph 1.3.)
2.2.1 The focusing operation shall not displace the picture by more than 1.0% of its width.
3. Projection Lens
3.1 Focal Length. In following sections, for test purposes, the use of a lens having a focal length of approximately 3]/2 inches will be assumed. (See Paragraph 1.3.)
P. 1 of 8 pp.
3.2 Resolution.
3.2.1 Resolution shall be defined and measured in accordance with American Standard Z22.53-1946, except that measurement shall be made with the standard picture width. (See Paragraph 1.3.)
3.2.2 The resolution shall be at least 80 lines per millimeter for the patterns identified as E and D and at least 90 lines per millimeter for all others.
4. Optical Axis
4.1 The projector shall include, or have available as an accessory, a sturdy pedestal. Means shall be provided to place the optical axis (when level) at any required height from 47 to 49 inches from the floor.
4.2 A tilting mechanism shall be included although this need not permit either quick change or change during operation. The range of tilt shall be sufficient to raise or lower by 1 inch an image of standard width, projected by a 3]/2-inch lens.
4.3 A leveling mechanism capable of rotating the projector about an axis parallel to the optical axis shall be included.
5. Film Gate
5.1 Dimensions. The dimensions of the picture aperture and its location relative to the film shall be in accord with American Standard Z22.8-1950.
5.2 Lateral guiding. At the picture aperture the sprocket hole edge of the film shall be used for lateral guiding. (Note: This is an exception to the recommendations of American Standard Z22.8-1950. For a discussion of the problem involved, see Note 3 of Z22.8.)
NOT APPROVED
August 1952 Journal of the SMPTE Vol. 59
145