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下图示意的是汽巴公司在英国专利2017945A中介绍的放大机灯箱,它能使操作者在使用可变反差放大纸时在大范围的反差级数中进行选择,而曝光时间不变。白炽灯4和5发出的光,分别通过滤色镜6和7,传递两个互不相交的波段的光,如黄色和品红色。光线自白聚苯乙烯漫射板10漫射之后通过抛光镜筒11到达乳白色漫射屏12,然后到达底片15。每只灯都用交流电,电流由一个三端双向可控硅开关控制,电导相角被一个微型处理机根据只读存储器储存的数据来确定。一个开关组14根据照片要求的反差,选择存储器中的交变地址。对存储的数据进行选择是为了使三端双向可控硅开关调节通过灯的电流。这样,当反差变化时,两个波段的光能量以反比变化。用这
Shown below is an amplifier light box introduced by Ciba in British Patent No. 2017945A, which allows the operator to choose from a wide range of contrast orders when using variable contrast magnification paper, with the same exposure time. The light emitted by the incandescent lamps 4 and 5 passes through the color filters 6 and 7, respectively, and transmits light in two mutually non-intersecting bands, such as yellow and magenta. The light-diffusing polystyrene diffuser plate 10 diffuses through the lens barrel 11 to reach the opaque diffusing screen 12 and then reaches the back sheet 15. Each lamp uses alternating current, the current is controlled by a triac, and the conductance phase angle is determined by a microprocessor based on data stored in read-only memory. A switch group 14 selects the alternate address in the memory according to the contrast of the picture request. The stored data is chosen so that the triac regulates the current through the lamp. In this way, the optical energy of the two bands changes inversely as the contrast changes. Use this