目前,一般印制黑白照片的曝光箱均为人工设定曝光时间,这样,常常难以得到一个理想的曝光参数,不是曝光过度就是曝光不足。这就需预先反复进行曝光参数试验,才能正式进行印相。使得在印相过程中不可避免地产生许多时间和材料的浪费,而且难于达到理想的效果。基于以上原因,我们进行了电子自动选时曝光箱的研制。这种曝光箱采用了光电检测系统对通过底片的光强进行自动测定,将测定光的强弱信号输入到自动控制曝光时间的控制系统,而后自动选定较为合理的曝光参数,对底片进行适量的曝 At present, the exposure boxes for printing black-and-white photos are manually set exposure times, so that it is often difficult to obtain an ideal exposure parameter, which is not underexposure or underexposure. This requires the trial of exposure parameters beforehand, in order to formally print. Making the printing process inevitably produce a lot of time and material waste, but also difficult to achieve the desired effect. Based on the above reasons, we conducted the development of electronic automatic time-selective exposure box. This exposure box uses a photoelectric detection system for automatic determination of the intensity of the light passing through the film, the intensity of the light signal input to the automatic control of the exposure time of the control system, and then automatically select a more reasonable exposure parameters, the film appropriate amount The exposure