Device for determining density differences of photographic negatives

摘要

433,701. Exposure meters. WEISSE, E., 1, Ludwig-Hupfeldstrasse, Leipsic, Germany. Jan. 15, 1934, No. 1459. Convention date, Jan. 13, 1933. [Class 98 (i)] The apparatus comprises a disc 2 adapted to be rotated over a disc 9 by a knob 14 the edge of the disc 9 being bent over the edge of the disc 2 to form a guide flange. The device is placed on the projected image of the negative at the printing level so that a gap 13 in the flange lies on the lightest part of the picture. By turning the disc 2, one of several screens of graduated density 3, 4, 5 and 6 is brought to the aperture which makes the combined density viewed by translucent or reflected light equivalent to the darkest part of the negative. The correct kind of paper to be used then appears in the aperture 10. The average intensity of the light on the printing level is now determined by comparing exposure measuring fields 7, 71. If, for example the necessary light value lies at 71, the correct exposure in seconds is read off at 81, such being computed with reference to the sensitivity of the kind of paper. Specification 416,026 is referred to.