拍照用的国产21°黑白胶卷,有《太行》、《公元》、《无锡》、《友谊》、《上海》、《吉林》、《青岛》和《厦门》等近二十个牌号。这些牌号的胶卷,近两年来它们的质量都有不同程度的提高。例如,在提高显影颗粒的细度、增加解像力的线数、丰富影像的层次等方面,都有所反映。但是,我们也应该看到,由于生产设备和工艺水平与国外比还存在很大差距,所以表现在产品质量上则是,显影颗粒比进口的粗一些、解像力比进口的 Photographed with a domestic 21 ° black and white film, “Taihang”, “AD”, “Wuxi”, “friendship”, “Shanghai”, “Jilin”, “Qingdao” and “Xiamen” nearly 20 brands. These grades of film, in the past two years, their quality has improved to varying degrees. For example, they are all reflected in improving the fineness of developing particles, increasing the number of lines of resolution, and enriching the image levels. However, we should also see that due to the large gap between the level of production equipment and technology and that of foreign countries, the performance of product quality is that developing particles are rougher than imported ones and resolution power is higher than that of imported ones