酸是影响纸张寿命的主要因素,对于民国时期报纸的酸度情况,我们一直缺乏全面、定量的认识。过去,我们主要是从直观和零星的检测数据来判断报纸的酸化情况,总的印象是民国时期报纸酸化现象严重,PH值低,纸张发黄变脆,急需进行保护和抢救。本文以中国第二历史档案馆馆藏的民国时期 Acid is the main factor affecting the life of the paper. For the newspaper’s acidity in the Republic of China, we have been lack of comprehensive and quantitative understanding. In the past, we mainly judged the newspaper’s acidification status from intuitionistic and sporadic test data. The general impression was that during the Republican period, the newspaper was acidified severely, the PH value was low, the paper was yellow and brittle, and it was in urgent need of protection and rescue. This article takes China’s second historical archives collection of the Republic of China period