Dataset: agedpapers.csv Source: C.H. Stevens, T. Barrett, P.M. Whitmore, J.A. Wade, J. Mazurek, M. Schilling (2008). "Composition and Condition of Naturally Aged Papers," Journal of the American Institute for Conservation, Vol. 47, #3, pp. 201-215. Description: Measurements on 40 aged documents of various content and chemical properties. Documents were classified as Dark or Light (20 each). Variables/Names specimen shade (1=Dark, 2=Light) country year gelCont (gelatin content, wt %) pH yellowIndx (yellowness index) dgrPolymer (degree of polymerization) Ca (calcium, ppm) Mg (magnesium, ppm) Al (aluminum, ppm) K (potassium, ppm) S (sulfur, ppm) Cu (copper, ppm) Fe (iron, ppm)