| 摘要 |
The exposure time of a reproduction camera 22 is automatically controlled by markings 12, 26 provided on the packaging 11 for the photographic material and which represent the sensitivity of the material and its emulsion number respectively. These markings are read by a read head 13 and stored in a memory 14. A decoder 15 is able to translate the stored information into a signal which is passed to a multiplier 24 and used to modify a basic time signal supplied from a coding switch 25 to the multiplier. The resulting signal is passed to a comparator 17. On receipt of a signal at the comparator 17 an exposure control device 16, which has been previously energized via start button 20 energizes the exposure lamps 21 and the exposure commences. A counter 19 starts a count at the beginning of the exposure period and this count is compared in the comparator with the signal received from the multiplier 24 and, as soon as equality is reached, the exposure control device is automatically switched off. The multiplier is also able to modify the exposure time via signals 30, 30' representative of the selected aperture and reproduction sizes.
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