Part IV.—Tests Applied to Paper and Paperboard and Their Significance

Acidity or alkalinity in paper may be caused by the presence of residual chemicals left in the pulp by the processes of manufacture, by chemicals added to the paper in order to obtain certain desired results, by chemicals absorbed from the air, or by contact with the skin when handled. Excessive acidity or alkalinity from whatever source may result in deterioration of the paper fibers in strength and durability.