The ISO 6588-1:2021 standard specifies a method for the determination of the pH value of aqueous extracts of paper, Cardboard and pulp, using the cold extraction method. This method involves the extraction of electrolysis from a sample using cold water and the measurement of its pH value in order to assess the acid alkaline of the material. The standard applies to all types of paper, Cardboard and pulp, but Measurement accuracy may be limited in the case of high purity pulps (e.g. with very little ionic material). Due to the use of distillation water or deionized water for extraction, the measured pH value may differ from the result under actual process conditions in the factory. At this time, reference may be made to ISO 29681 or the Miscellaneous Applicable standard. This standard provides an important chemical analysis basis for quality control and environmental assessment in the paper industry.