Nation projector carbons (1935)

Page scan 00088 from Nation projector carbons

Record Details:

Title:
Nation projector carbons
Date:
1935
Publisher:
Toronto : Canadian National Carbon Company Ltd.
Volume:
Nation projector carbons
Leaf #:
00088
Language:
English
Subjects:
Motion Pictures, Motion Picture Technology
Collection:
Books
Format:
Books
Contributor:
Media History Digital Library
Sponsor:
Media History Digital Library
Coordinator:
Media History Digital Library
Date Added:
May 15, 2025
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National Projector Carbons i SHUTTER OPEN t SHUTTER CLOSED / A. Low-intensity 60-cycle alternating-current arc B. High-intensity 60-cycle alternating-current arc C. Low-intensity rectified-current arc Figure 67 Oscillograms of Instantaneous Light on Projection Screen; Two-Bladed Shutter, 1440 r.p.m., Corresponding to Film Speed of 90 Feet Per Minute more closely to the curve of the light obtained from the D.C. arc operating on rectified current with the shutter running. The practical proof of this is obtained by observing the projection of the same amount of light from the three types of arcs with the shutter running. This has been done in the laboratory with a very high degree of illumination on the screen and without film in the projector, the conditions under which fluctuations in light are most noticeable. Observations under such conditions agrees with the conclusions arrived at from the oscillograms; namely, that the light beat or fluctuation of the high-intensity A.C. arc is very much less than that of the lowintensity A.C. arc and of essentially the same magnitude as that of the low intensity D.C. arc using neutral cored carbons and operated by a single phase 84