酸化程度為紙張劣化的重要指標。近年來保存科學及檔案維護領域，常以紙張酸鹼值（pH值）作為評斷紙張劣化的依據。紙張酸鹼值測試有其侷限性，起因為樣品及溶劑量、操作條件以及紙張基本性質等因素。其中，樣品與溶劑量直接影響水中鋞離子濃度[H3O+]；不同的操作溫度，會影響紙張內物質的溶出以及纖維素、半纖維素、木質素的水解；紙張的基本條件如種類、造紙方式、添加物及表面結構等等，也會影響紙張內物質溶出的速度。 本研究以紙張酸化相關研究中的直接測量法、冷水萃取法、熱水萃取法等方法，進行實作及評估，實驗材料為銅板紙、道林紙、印書紙、再生紙、影印紙等五種市售現代紙。結果顯示，多數研究中使用的直接測量法，經過十次重複的驗證，所得的數據差異極大，各類紙張酸鹼值分布的範圍：銅板紙5.44~5.88、道林紙4.18~4.80、印書紙4.40~5.72、再生紙5.02~6.10、影印紙5.15~6.18，最大及最小值差異百分比：銅板紙8.08%、道林紙14.83%、印書紙29.55%、再生紙21.15%、影印紙20.00%，檢測數據的穩定性略顯不足。而利用熱萃取法進行量測時，在一八○分鐘內每二十分鐘量測一次，數值呈現不穩定，數據無代表性。冷萃取法在初期呈現的數值不穩定，然而在一定時間之後漸趨於穩定。為因應紙張酸化研究的需要性，以及新的方法、理論尚待討論與研究的情況下，本研究建議暫以冷水萃取法進行紙張酸鹼值檢測。

　　　　　Acidic level is an important index for observing paper deterioration. In recent years, in the field of preservation science and document maintenance, paper pH value is usually used as a reference to evaluate paper deterioration. Paper acidic/basic test has its limitation, because it is affected by factors such as: sample and solvent quantity, operating conditions, and the basic properties of the paper. Sample and solvent quantity will affect directly the H3O+ concentration in the water. Different operating temperatures will affect the dissolution of material contained in the paper, and the hydrolysis of cellulose, hemi-cellulose and lignin. The basic properties such as categories, paper manufacturing method, additives and surface structures will affect the dissolution speed of the material contained in the paper. This study conducts experiments and evaluations by using the direct measurement method, cold water extraction method, hot water extraction method, etc., which are commonly used in paper acidification related studies. The experimental materials are five kinds of paper available from the market such as: coated paper, printing paper, book printing paper, recycling paper, copy paper, etc. The results show that the direct measurement method most commonly used in lots of studies leads to big data variance after 10 times of repeated verifications. The acidic/basic value distribution ranges for these papers are: 5.44 to 5.88 for coated paper, 4.18 to 4.80 for printing paper, 4.40~5.72 for book printing paper, 5.02 to 6.10 for recycling paper, 5.15 to 6.18 for copying paper; and the differences in percentage between the maximum and the minimum values are: 8.08% for coated paper, 14.83% for printing paper, 29.55% for book copying paper, 21.15% for recycling paper, 20.00% for copying paper. The stability of the obtained data is not good enough. When the measurement is performed by using hot water extraction method, one measurement at 20-minute interval within a period of 180 minutes, the measured data shows unstable and non-representative. For the cold water extraction method, the measured data is unstable at the initial stage, but tends to be stable in certain amount of time. Due to the urgency requirement of paper acidification research, and under the condition that the new method and theory still need to be thoroughly discussed studied, this study thus suggests that the cold water extraction method be used for paper pH value test.