Looking at Art, Artifacts and Ideas | by David Cycleback
Materials of organic origin such as leather, parchment andartifacts in which cellulose fibers such as paper products form thesupport are likely to be soiled and stained by solid particles ofcarbon, tarry matters and other solid contaminants. The worsecontaminants for this group of materials are sulfurous and sulfuricacids resulting from the combustion of fuels and from otherindustrial processes. The effects are severe with cellulosematerials such as paper and leather. There is a close correlationbetween the loss of strength of paper and its acidity resulting fromsulfuric acid contamination. Dust and dirt particles in the air notonly carry with them the adsorbed pollutants mentioned above but mayexert an abrasive action on books and paper.
Photocopier Hazards and a Conservation Case Study - …
Eventually more effective drum-type washing screens that ran in the Hollander tub superseded the splash frames. Hunter attributes the first use of such a device to Hall of Dartford, England, in 1832 (Hunter, Papermaking, 546). By this time, however, washing during beating had become essential, not so much to lighten the color of fermented rags, but to clear the cooking chemicals and bleaches that had replaced the more traditional steps. The small washer used in section 3.1 of the 1989 study is based on these early English washers. See Barrett, “Early European Papers,” 57–65.
While it is unlikely that papermakers were knowledgeable about the contribution of calcium and magnesium carbonate to paper permanence, they would easily have noted the ill effects of water high in iron content by the reddish or brownish cast it gave their paper. The historical papers with lighter and less red colors analyzed during this research contained higher calcium and lower iron concentrations. Calcium compounds such as lime are known to have been use in early papermaking. Józef Drabowski and John Simmons cite F. M. Grapaldo's 1492 description of the addition of lime to the stamper pits. This was likely done to help swell the cellulose and expedite fiber shortening and fibrillation during stamping. Ground chalk might have been added in small amounts as a whitener to counteract the yellowing effects of retting or iron in the water. Limed skins and other animal parts used to make gelatin size may have been another source. Finally, at least a portion of the calcium compounds entered the paper via the water supply. Calcium and magnesium carbonate can appear as sources of hardness in ground and surface water. During papermaking, cellulose fiber very rapidly accumulates metals dissolved in water, be they favorable or unfavorable to the permanence of the paper.