There are large number of fading, mildewing, turning yellow black-and-white photographs in museums and archives, which seriously influence the value of image preservation and historical signification.

• 然而收藏在博物馆和档案馆的早期黑白照片大多出现了影像消褪、变黄、霉变等现象,严重影响了照片档案的保存价值和历史研究价值。