Journal of the Society of Motion Picture Engineers ( Volume: 33, Issue: 11, November 1939)

[ACTIVE]

A Direct Positive System of Sound Recording

Metadata

Publisher: SMPTE
Doc Type: Journal Article
Article Type: research-article
Abstract: One of the fundamental advantages of the variable-area system is that the original negative may be reproduced directly without appreciable wave-shape distortion. One printer operation can be eliminated and the film noise considerably reduced by originally recording a track in which the transparent area diminishes as the recorded level is decreased. A direct positive recording system has been so designed that the recording and noise-reduction light-beams are separated in the direction of the film motion. This allows the noise-reduction system completely to anticipate a coming signal, thereby eliminating clipping. When the sound volume is less than is required to fill the track, the noise from the direct recording is reduced further by additionally exposing those portions of the track not needed for the sound-waves. A single shutter vane automatically controls both the transparent area and the additionally exposed area. A model of the direct positive optical system has been on test in Hollywood for several months. The exposure has proved to be less critical than on the negative-print process. Densities from 0.80 to 1.60 produced only minor quality differences. A good print of a negative compares favorably in quality with a direct positive record, but because of the variations always present in the printing operation, it is believed that a higher average of quality can he maintained from the direct record.
Publication Date: 1939-11-01
DOI: 10.5594/J11917
Link: https://doi.org/10.5594/J11917
Author(s): G. L. Dimmick, A. C. Blaney

Source Data (JSON)

Full registry record with provenance metadata. Open directly: /api/doc/10.5594-J11917.json

Reference this Doc

Plain text (ISO 690 compliant)

Preview:

G. L. Dimmick and A. C. Blaney; A Direct Positive System of Sound Recording, Journal of the Society of Motion Picture Engineers ( Volume: 33, Issue: 11, November 1939); SMPTE, 1939. Available at https://doi.org/10.5594/J11917

Snippet:

G. L. Dimmick and A. C. Blaney; A Direct Positive System of Sound Recording, Journal of the Society of Motion Picture Engineers ( Volume: 33, Issue: 11, November 1939); SMPTE, 1939. Available at https://doi.org/10.5594/J11917

HTML (ISO 690 compliant)

Preview:

Snippet:

<span class="citation">G. L. Dimmick and A. C. Blaney; <cite>A Direct Positive System of Sound Recording</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 33, Issue: 11, November 1939); SMPTE, 1939. Available at <a href="https://doi.org/10.5594/J11917" target="_blank" rel="noopener">https://doi.org/10.5594/J11917</a></span>

SMPTE's HTML Pub

Preview:

Snippet:

<li>
G. L. Dimmick and A. C. Blaney; <cite id="bib-10-5594-j11917">A Direct Positive System of Sound Recording</cite>, Journal of the Society of Motion Picture Engineers ( Volume: 33, Issue: 11, November 1939); SMPTE, 1939
<span class="doi">10.5594/J11917</span>
</li>