AIC 53rd Annual Meeting

Books are kinetic objects that perform finely-engineered movements to reveal their contents. If a book’s structure is broken or compromised, its information cannot be experienced in the manner that its creator intended. Loss of mechanical function is particularly disruptive for manuscripts, artist’s books, photograph albums, and scrapbooks, in which unique, intimate narratives may be presented. In some ways, nineteenth century photograph albums present worst-case treatment scenarios to conservators; these albums tend to be both heavy and very fragile, due to inherent vice, yet these albums may be frequently requested by researchers. Furthermore, photographs are physically and chemically sensitive, and nineteenth century papers are often quite water sensitive, which limits treatment options. As heavy leaves and delicate hinges embrittle with age, a nineteenth century album may pull itself apart, posing many questions; is it possible to restore mechanical function to this album without frequent re-interventions? Which materials are best for reinforcing the connections between heavy leaves and delicate hinges? Do adhesive mixtures, such as 75% wheat starch paste and 25% methylcellulose, provide better flexibility when dry?

The above questions inspired this study, in which the author, a book conservator, collaborated with paper conservators, photograph conservators, and conservation scientists at the Metropolitan Museum of Art. This presentation will discuss the methodology and results of the study, in which the relative folding endurances of Jin Shofu wheat starch paste, photo-grade gelatin, and six cellulose ethers were evaluated, before and after artificial aging. Additionally, 3:1 mixtures of wheat starch paste, methylcellulose, and/or photo-grade gelatin were studied, to observe the mechanical performances of these mixtures, once dry. To inform the methodology of this study, a self selecting survey of seventy-five AIC Book and Paper Group members was conducted. Survey participants were asked to indicate their adhesive preferences for certain treatment scenarios, and whether they are in the habit of combining two or more adhesives to alter their wet and/or dry properties. In this study, all adhesives were prepared at concentrations that would normally be used by book, paper, and photograph conservators, or at viscosities that would allow a conservator to reline the spine of a book or repair its hinges. Strips of naturally aged chromatography paper (pure cotton linters, manufactured in 1959) were impregnated with these adhesives and were evaluated with a Tinius Olsen folding endurance machine. Although folding endurance machines do not perfectly replicate a book’s normal range of motion, these machines offer insight into the effects that adhesives and sizing agents may have on the mechanical strength of a standard paper.

The surprising results of this study indicate that wheat starch paste has a much lower folding endurance than cellulose ethers with comparable bonding strengths, and that mixing two adhesives together significantly impacts the folding endurance of a standard paper, both before and after artificial aging. The author hopes that the results of this study may assist book, paper, and photograph conservators when selecting resizing agents and when repairing the flexible components of books and moveable paper objects.