| 摘要 |
The invention relates to a method for controlling exposure during colour copying, having three individually photoelectrically controlled colour exposures, it being the case that in each colour the first step is to measure, for the purpose of calibrating the paper sensitivity, the copying time tEi required to achieve a copy with an average contrast of a calibration negative, whereupon corrections (slope) performed in order to take account of deviations in sensitivity between photoreceiver and copying material, and colour undercorrections performed in order to suppress colour casts are added to the calculated copying times. In order to avoid the difficult adjustment of the intensity of the exposure beam path in such a way as to produce three equally long colour exposure times for a calibration negative, the copying times arising in the case of the existing copying light brightness are stored in the three colours for the calibration negative, and the correction values for slope and colour undercorrection are taken into account by computer when calculating the copying times for a measured negative, starting from the different exposure times for the calibration negative. <IMAGE>
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