F. H. Richardson's bluebook of projection (1935)

Record Details:

Title:
F. H. Richardson's bluebook of projection
Date:
1935
Publisher:
New York : Quigley Publishing Company, Inc.
Volume:
F. H. Richardson's bluebook of projection
Leaf #:
000240
Language:
English
Subjects:
Motion Pictures, Motion Picture Technology
Collection:
Books
Format:
Books
Contributor:
Media History Digital Library
Sponsor:
{"Media History Digital Library","Jeff Joseph"}
Coordinator:
Media History Digital Library
Description:
Date Added:
August 01, 2024
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222 RICHARDSON'S BLUEBOOK OF PROJECTION covered with vaseline and protected from rust it will last a lifetime. Aperture Tension (54) When there is too little tension the screen image is unsteady. (55) Too much tension, on the other hand, imposes a great strain upon many parts of the intermittent mechanism, chiefly upon the delicate edges of the sprocket holes of the film, upon the motor that drives the projector, upon the projector gear train and consequently upon the shaft bearings which give the gears their support, and generally upon all working surfaces of the intermittent movement including the edges of the sprocket teeth and the tension shoes and aperture plate film tracks. Even under the best of conditions the intermittent mechanism represents a sensitive adjustment of precisely accurate parts working at top speed under strain. Some sections of the intermittent assemblage must start, reach high speed and stop twentyfour times each second for long and . continuous periods of time each day. This truly "nerve-wracking" action takes place against the braking effect of the aperture tension. (56) If the tension applied at the gate is just enough to permit the film to stop perfectly still for a brief interval over the aperture (without unsteadiness or overshooting of the screen image), then the intermittent is accomplishing its work smoothly. But if the aperture tension is excessive, the actuating pin D in Fig. 62 will press against the side of the star slot with sufficient force to overcome the pull of normal tension and this added to the excessive tension at the aperture will, in time, destroy Figure 65