在黑白照片放大制作时,常遇到底片密度偏小、反差偏小的情况,这样的底片很难放制出最佳效果,这时就要去做底片加厚处理。首先要选用聚光式的放大机,其次要选配高反差的显影药液,再选用特硬性的黑白放大相纸。特别要注意的是相纸曝光时要把放大镜头的光圈尽量开得大一些来缩短相纸的曝光时间,让曝光后的相 In the black and white photo enlarge production, often encounter negative film density, contrast is small, such a film is difficult to produce the best results, then we must do the film thickening treatment. First of all, to choose a condenser magnifier, followed by matching high-contrast development liquid, and then use the special hard-black and white photo paper. Special attention should be paid when the photographic paper exposure to enlarge the lens aperture as much as possible to open the photo paper to shorten the exposure time, so that the exposed phase