(Im)mortal Photographs

The Kórnik Library of the Polish Academy of Sciences houses magnificent historic collections, which include numerous old photographs. Most of these are silver prints on paper substrates. The dominant photographic technique used by nineteenth-century photographers was albumen prints (the “printing-out paper” technique, POP), while silver-gelatin prints (the “developing-out paper” technique, DOP) were predominant among twentieth-century photographers. For years, the Kórnik Library has been making efforts to protect its collections through continuous cooperation with conservators – including with our team from the Department of Conservation and Restoration of Paper and Leather at the Nicolaus Copernicus University in Toruń. Photographs are a type of historical object that is extremely sensitive to a variety of destructive factors. These first and foremost include excessive daily fluctuations in humidity and temperature, biological factors (insects, microorganisms), improper use and storage, and air pollutants. From a conservator’s point of view, “air pollutants” are understood as any undesirable solid, liquid, or gaseous substances that may have a negative effect on the durability and permanence of a historical object. Objects created on paper substrates may be harmed by various chemicals present in the air: acidic oxides, volatile organic compounds – VOCs (especially acidic VOCs), substances that accelerate the oxidation process (peroxides, ozone), and hydrogen sulfide. Many of these were the subject of research we carried out between 2011 and 2016, where indicator tubes were used to draw in air Tomasz Kozielec, PhD, DSc