Excerpt from The American Annual of Photography, 1912 Secondly - Set the movable scale until this Actinometer Time is against the Speed Number of the Plate to be used, then against every stop in outer scale will be found the correct corresponding exposure, or, shortly you set the one Scale, it does the rest. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com 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.