AIC's 43rd Annual Meeting

An ideal treatment begins with a knowledge of materials and the chemical reactions that cause condition problems. Many works of art on modern papers are known for their conservation treatment challenges. Modern papers appear to age quickly and may not respond predictably to typical conservation treatment procedures. Stains and discoloration that have been successfully addressed will reappear, in some instances, almost immediately after treatment. Because of serious omissions in theory, paper conservators lack accurate information about the complexity of modern paper. The field of paper conservation has adopted terminology from the paper making and paper testing literature. Discoloration and stains that develop in works of art over time are not taken into account by the industry and its testing body, which assess brightness, paper folding strength and fiber tensile strength of un-aged samples, often using specially-prepared test papers. In general, paper condition is described in terms of cellulose. In this talk, an alternative interpretation of condition problems is proposed, based on systematic examination and treatment of late nineteenth- and early twentieth-century works of art on paper. Beginning in the nineteenth century, and inherent to the science of paper making today, non-fibrous, inorganic additives were routinely and selectively added to fiber stock to increase opacity, modify texture and absorption, aid in ink retention, fill gaps, and determine paper tone. When selected for a work of art, these complex substrates undergo rigorous, unpredictable and uncontrolled processes. Over a long lifetime, many works of art on paper reside in unstable environments with fluctuating temperatures and humidity. Affixed to a wall, they may be exposed to acidic mats and unfiltered daylight for decades. These papers are also subject to intervention by restorers, framers and paper conservators. Over time, works of art on modern papers may develop “foxing” or “reverse foxing” stains, become “light stained” within a window mat, “time stained” at a sheet’s edges or “burned” by acids exposed at the bevelled edge of a poor-quality mat. Apart from the aluminum sulfate in alum-rosin sizing, the role that inorganic additives may play is not acknowledged in the paper conservation literature. Yet, the mineral and metal oxide pigment additives employed by the paper industry are not inert in the conditions that are known to cause damage to works of art. Present in trace amounts and most often evenly distributed throughout the fibrous cellulose web, additives are often overlooked by non-destructive, qualitative analysis. Based on treatment experience, close observation, analysis and study of reflectance and fluorescence under ultraviolet illumination, this talk will discuss the significant role that inorganic additives play in condition, conservation treatment and results.