Processing of Ultraviolet Recordings on Panchromatic Films*

Abstract

The necessity in newsreel work of making the original sound recording on panchromatic film has always meant a serious sacrifice in quality and ground-noise ratio, as compared with results that can be attained when sound is recorded on a separate film. While ultraviolet recording materially increases fidelity of response, with panchromatic as well as with standard sound negative film, the low contrast and high base fog of panchromatic film processed for negative picture development produce noise and considerable reduction in volume range. — The track density on the panchromatic film is rather low, of the order of 1.0 to 1.2, when recorded with a practical optical system for a single-film system. When this track is printed on commercial release print stock the dense portion of the negative track will print through, producing a fog density in the clear portion of the printed track. This fog in the clear portion tends to produce noise and reduces the volume range. When the panchromatic negative and print are processed in accordance with commercial practice, the reduction in volume range is of the order of 6 db. — Printing panchromatic negative upon a high-contrast emulsion improves both the noise and volume range. Since the release prints must be on standard picture positive stock and not on high-contrast film, it is proposed to make a master positive on high-contrast emulsion and to re-record from this to a standard sound negative, which would be used in the ordinary way to make the release prints. An improvement in release print ground-noise of 8 to 12 db. is obtained by this method, and the volume range is increased by 6 db. Briefly, the proposed method is a means for increasing the density contrast of the final release print track when the original is recorded on panchromatic film.