Excerpt from A Nonintermittent Senistometer (Time-Scale Exposure Machine) With Clock-Controlled Motor Drive The design of a sensitometer must depend considerably upon the special nature of the work for which it is to be used. Of previous designs two by Jones (4) of nonintermittent sensitometers are note worthy. The exposures in the first are controlled by a solenoid which moves a shutter plate in steps in front of the photographic material. The time intervals of the steps are determined by the spacing of perforations in a ...
Read More
Excerpt from A Nonintermittent Senistometer (Time-Scale Exposure Machine) With Clock-Controlled Motor Drive The design of a sensitometer must depend considerably upon the special nature of the work for which it is to be used. Of previous designs two by Jones (4) of nonintermittent sensitometers are note worthy. The exposures in the first are controlled by a solenoid which moves a shutter plate in steps in front of the photographic material. The time intervals of the steps are determined by the spacing of perforations in a strip of motion-picture film driven at a constant rate, through which an electrical contact lever operates. The timing of this machine may be changed by substituting another strip of film having perforations spaced to suit the requirements. This sensitometer is adapted for use with small light intensities only as the shutter can not be moved with sufficient precision for exposures less than one-fourth of a second. The other machine by Jones (5) is of the sector-wheel type in which the exposures take place during one revolution only. The speed of the sector wheel is variable through the enormous range of from to 0000614 r. P. M. All of this range is not available, however, as the light - Operating mecha nism was found not to function satisfactorily at the higher velocities. Apparently the maximum operating speed is 320 r. P. M. The sec tor wheel is 30 inches in diameter, has 10 steps in the usual power of-two ratio, and the largest aperture is This instrument was designed primarily for a study of the reciprocity law. Jones (6) and Higson (7) describe two machines in which an aperture plate is moved in a linear motion; the first one mentioned has step apertures, the other is a continuous wedge - shaped aperture. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at ... This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.
Read Less
Add this copy of A Nonintermittent Senistometer (Time-Scale Exposure to cart. $14.39, new condition, Sold by Paperbackshop rated 4.0 out of 5 stars, ships from Bensenville, IL, UNITED STATES, published 2019 by Forgotten Books.
