不同密度的底片,在制作时使用不同反差的相纸,可以得到满意的照片。但是,在一些特殊情况下,相纸型号不全,譬如手中只有三号、四号较硬性相纸,而底片的密度只适合一号或二号相纸洗印。此时,就需要采取措施,以俾降低相纸反差,制出满意的照片。为此,根据自己实践经验,介绍几种比较安全、稳妥、简便易行的方法如下: Different density of the film, the use of different contrast in the production of photographic paper, you can get a satisfactory picture. However, in some special cases, the paper model is not complete. For example, only the No. 3 and No. 4 hard photo papers in the hand are used, and the density of the negative film is only suitable for the photographic printing of No. 1 or No. 2 paper. At this point, we need to take measures to reduce the contrast of photographic paper, to produce satisfactory photos. To this end, according to their own practical experience, introduce several more safe, secure, easy and simple method is as follows: