Eggs have been widely utilized by artists in different types of media. They have been used as a glossy coating for watercolors; in tempura paints as a binder; and as a means of preparing a surface for applying gold leaf. So it should be of no surprise to find that they were used as a part of a nineteenth century photographic process. The egg white or albumen may also be referred to as glair. This proteinaceous substance has been used as the initial coating on paper prior to sensitizing with silver nitrate for photographic printing. It filled in the crevices between paper fibers, allowing for a more detailed image, and created an appealing pearly sheen. If you have ever allowed spilled, uncooked egg whites to dry on a countertop, you may have noticed how they left behind a hard and glossy surface.
The albumen printing process is the most common type of paper photograph found in collections that date from the mid-1850s to the end of the nineteenth century. It was widely used for all formats and sizes of prints, including cabinet cards, stereoviews, cartes de visite and mammoth prints. You most certainly have seen one, either in a museum, an antique store, or even your own family photo collection. There are countless albumen photographs out there, but not all are created equal. Unfortunately, the vast majority of them have experienced deterioration caused by a variety of evils, including pollutants, light, and poor processing techniques.
One deterioration characteristic often used to identify albumen prints is yellowed and faded highlights. There are a few pristine albumen prints in existence, thanks in part to gold chloride toning, which enhanced the permanence of the silver and created an attractive deep eggplant toned image. However, it is quite rare to find examples with clean, bright highlights and no objectionable yellowing or fading. For longevity, these prints require proper care, and the rare examples in good condition are especially deserving of proper storage.
The problems of impermanence of the albumen print were recognized early on in the inception and use of the medium. Fading and discoloration were concerns brought forth as early as 1866 in publications like the the <em>Photographic News</em>, which introduced the need for proper development, washing, and fixing in the processing of albumen prints, in order to provide a longer-lasting image.
A number of studies focusing on albumen print conservation were carried out in the late twentieth century. The problem of yellowing in albumen prints was studied by conservators. The cause is the Maillard reaction, or protein-sugar reaction, which is also the chemical reaction responsible for browning of foods during cooking. This reaction is driven by heat.
Other studies confirmed that the problematic cracking of the albumen binder was caused by exposure to water and high humidity. Over time, repeated exposure to humidity fluctuations exacerbates binder cracking, which eventually develops into flaking and loss of the image. Unlike gelatin photographs, which can expand and contract with humidity changes, albumen does not expand in the same way as the photographic paper support. This causes strain in the albumen layer, creating cracks.
Albumen prints are a printing-out process, meaning that the development is by sunlight, at which time the image appears. Since these photolytic silver image particles are spherical and extremely small, they have a large surface area to react with pollutants and light. The albumen print is therefore subject to oxidation and fading by these factors. Deteriorating pollutants may come from lignin in wood pulp paper enclosures, cleaning products, paints, adhesives, or combustion products, to name a few. When fading occurs, it usually is most obvious as loss of detail in the highlight areas of the image.
Albumen prints are nearly all mounted, due to the thinness of the paper used and the natural tendancy of the coating to cause the print to curl into a very tight “cigarette.” Some of these mounts are decorated with bronze powders, used to create golden borders or studio printing. The zinc in bronze powder is capable of causing local spots of fading on albumen photographs.
In short, the best way to preserve albumen photographs is to store them in individual polyester film sleeves or paper enclosures, away from heat, sunlight, humidity fluctuations, and sources of pollutants. Enclosures should be made of acid and lignin-free paper. Buffers added to some papers may interact with the albumen print, if they become water damaged, so papers with added calcium carbonate should not be stored in direct contact with these prints.
For additional examples of albumen prints, see the previous post Photographic Amusement: Stereoviews, which shows some prints in Hagley’s collections. The stereoviews in that collection exhibit localized fading caused by sulfur and/or oxidizing compounds in the mounting adhesive and edge fading due to pollutants from acidic storage containers.
For more information and literature on the history and conservation of albumen photographic prints, visit the Albumen website.
Laura Wahl is the Library Conservator at Hagley Museum and Library.