| 摘要 |
PROBLEM TO BE SOLVED: To avert an increase in the size and cost of the device and to execute the negative and positive discrimination of films by providing the device with a discriminating means for executing the negative and positive discrimination of the films in accordance with the signal from a film detecting means. SOLUTION: An output signal level rises up to Es according to the high reflectivity of a reflection plate in perforation parts. In non-perforation parts, on the other hand, the output signal level falls low but this level depends upon the reflectivity of the film. The positive film after development is black in unexposed portions exclusive of photographing image plane portions and since both of the reflectivity and transmittance in these portions are low and, therefore, such a low output level like Ep is attained. The negative film, as against the same, is relatively high in the transmittance in the unexposed portions exclusive of the photographing image plane portions and the component which is reflected by the reflection plate and is received in a photodetector is a ratio of the certain extent and, therefore, the output level like En slightly higher than Ep is attained. The negative and positive discrimination is, therefore, executed by detecting this difference.
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