A METHOD FOR THE DEACIDIFICATION OF PAPERS AND BOOKS

A simple method for the deacidification of paper sheets has been devel oped and tested on a variety of papers. The method consists of placing the sheet to be deacidified in intimate contact with an alkaline shee t of paper containing calcium carbonate. With time, ions migrate betwe en the sheets resulting in the neutralization of the hydrogen ions of the acidic sheet by ions derived from the calcium carbonate of the alk aline sheet. However, deacidification only proceeds at a useful rate i f the sheets are initially conditioned at a high relative humidity and this humidity is maintained while the sheets are held together under an applied pressure. At 97% RH and 350 kPa (50 psi), deacidification c an often be completed in less than a day. Other factors such as the ro ughness and the electrolyte content of the sheets in contact are also important in determining the treatment time. The method as advantages over other deacidification procedures in that it uses benign, inexpens ive, readily available materials and equipment. The method can be appl ied to acidic books by interleaving the pages with alkaline sheets.