Optic projection : principles, installation and use of the magic lantern, projection microscope, reflecting lantern, moving picture machine, fully illustrated with plates and with over 400 text-figures (1914)

Record Details:

Title:
Optic projection : principles, installation and use of the magic lantern, projection microscope, reflecting lantern, moving picture machine, fully illustrated with plates and with over 400 text-figures
Date:
1914
Author:
Gage, Simon Henry, 1851-1946
Publisher:
Ithaca, N.Y. : Comstock Publishing Co.
Volume:
Optic projection : principles, installation and use of the magic lantern, projection microscope, reflecting lantern, moving picture machine, fully illustrated with plates and with over 400 text-figures
Leaf #:
000478
Language:
English
Format:
Books
Contributor:
Gerstein - University of Toronto
Sponsor:
MSN
Coordinator:
Media History Digital Library
Description:
Bibliography: p. 693-703
Date Added:
July 19, 2022
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CH. XII] BRIGHTNESS OF SCREENS 463 FIG. 249. DISTRIBUTION OF APPARENT BRIGHTNESS WITH DIFFERENT SCREENS WHEN VIEWED FROM DIFFERENT DIRECTIONS. On the sides and curved surface are given the degrees of inclination of the reflected light. The numbers along the central radius indicate the relative brightness of each screen, magnesium oxide being used as the standard and called 100%. A Magnesium oxide screen. It gives the standard brightness of 1 00% and reflects nearly equally throughout the entire 180 degrees. B White cardboard. C Screen with aluminum bronze facing. This gives 3.2 times the brightness of magnesium oxide in the center, but it falls off rapidly at the sides. E Mirror screen. This gives 7. 1 times the brightness of magnesium oxide in the center. It is to be noted in general that the mirror screens, (C. E.) give great intensity when seen near the center, and that this intense light is restricted to an angle of about 25 degrees. Farther to the side the light falls off rapidly, being in marked contrast with the white screens (A B).