This standard specifies methods for determining the pH value on the surface of paper and Cardboard, especially for paper and Cardboard with low surface water-absorption, including books and archives in library collections. By dripping water on the surface of the specimen and using a flat head electrode to determine the pH value, the standard ensures the accuracy and Reliability of the test. The requirements for the use of related equipment such as pH Meters and thermometers are also detailed to ensure the Accuracy of the test results.