1.1 This specification covers manifold papers used in preparing typewritten copies of permanent or semipermanent records and documents. The original, or ribbon, copy usually leaves the organization in which it originated, so the carbon copy becomes the copy of record.

1.2 It has been shown (1, 2, 3, 4, 5) that permanence is at least an approximate function of the pH of an aqueous extract of the paper with correlation coefficients ranging from approximately 0.7 to 0.9 (4). Three pH levels, reflecting three levels of permanence, are specified. Extract pH as an indicator of life expectancy is not valid if a paper has been treated with an alkaline surface size or if an alkaline coating has been applied.

1.3 The following would be expected to contribute significantly to the life expectancy of manifold papers: the use of papers with controlled acidity, or of papers manufactured under neutral or alkaline conditions, especially papers with a calcium carbonate filler that absorbs acidic gases from the atmosphere and can neutralize acidic materials formed in the aging of paper.

1.4 This specification is based on fiber sources used in the production of paper that contains no more than 1% lignin, for papers used in archives, libraries, and other permanent records. However, under proper conditions, (see Appendix X1.5), paper containing more than 1% lignin may be employed for many other end uses in paper for records that are required to have a substantial life expectancy.