ASTM D778-97(2007)

The acidity or alkalinity of a paper sample extract is important because of the effect of paper acidity or paper alkalinity on the permanence of the paper. Although acidity or alkalinity may be determined by titration the pH is often more indicative of the stability of paper than is the total acidity or alkalinity.

1.1 These test methods cover two procedures for determination of the hydrogen ion concentration, expressed in terms of pH, of an aqueous extract of paper.

1.2 These test methods may be applied to writing, printing, and sized industrial papers.

1.3 These test methods are not intended to be used for determination of pH of insulating papers, for that see Test Methods D 202.

1.4 The test methods appear as follows:

1.5 Specifications may be based on Test Method A or Test Method B, or both.

1.6 Where a specification or specific instructions or agreement to use only one of these test methods is absent, determine pH using both procedures, and interpret results based on Section 12.

1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.