The Effect of Different Sizings on the Rate of Aging in Paper

Abstract

The purpose of the experiment was to test the effect of different sizings on aging in paper. Most paper made from the middle of the 19th century deteriorates within decades. This creates a severe problem as information stored in books and documents is lost. It is important to know what causes the deterioration so that it can be prevented.

The hypothesis was that deterioration in paper is related to acidity, that acidity is related to type of sizing used, and that paper with high acidity will deteriorate faster. Seven sets of paper were made using different sizings. Half of each set was aged about 25 years by heating in an oven at 100° C for 72 hours. The cold extraction method was used to measure acidity before and after heat aging.

Discoloration and tear resistance were used to estimate deterioration. Effectiveness of sizing was tested by degree of feathering when written upon and by resistance to water. The paper samples with alum rosin sizing had the highest acidity, greatest increase in acidity with aging, and showed the greatest deterioration. The difference in rate of deterioration between it and the other samples was slighter than expected, showing that the fiber used is significant in permanence even when the sizing produces acidity. The alkyl ketene dimer was superior in low acidity and in resistance to water, followed by the gelatin size. The performance of the alkyl ketene dimer was constant with aging; all other samples improved in sizing with aging.

Keywords: deacidification, paper, media permanency, archival preservation