Hand-colouring of Photographs - Preservation and Storage

Preservation and Storage

In general, the preservation of hand-coloured photographs is similar to that of colour and monochrome photography. Optimal storage conditions include an environmentally controlled climate with low relative humidity (approximately 30-40% RH), temperatures under 68 degrees Fahrenheit (20 degrees Celsius), and a low concentration of particulate pollution, such as sulfuric acid, nitric acid, and ozone. The storage area must also be clean and free of pests and mould. Because hand-coloured photographs, like colour photographs, are more sensitive to light and UV radiation, storage should be in a dark location. The storage area should be secure and monitored for internal threats – such as change in temperature or humidity due to HVAC malfunction, as well as external threats, such as theft or natural disaster. A disaster plan should be created and maintained for all materials.

When handling cased photographs such as daguerreotypes, albumen prints, and tintypes, especially ones that have been hand-coloured, caution is required. They are fragile and even minimal efforts to clean them can irreparably damage the image. Hand-coloured cased photographs should be stored horizontally, in a single layer, preferably faced down. Cases can be wrapped with alkaline or buffered tissue paper. If the photograph has become separated from its case, a mat and backing board can be cut from alkaline buffered museum board. The mat is placed between the image and a newly cut glass plate while the backing board supports the image from behind. This "sandwich" is then sealed with Filmoplast tape. Commercial glass cleaners should not be used on new glass plates. Loose hand-coloured tintypes can be placed between mat boards. If bent, no attempt should be made to straighten them as this could cause the emulsion to crack and/or lift.

Ideally, all photographic prints should be stored horizontally, although prints under 11"x14" and on stable mounts can be safely stored vertically. Prints should also be stored away from light and water sources in acid-free, lignin-free boxes manufactured using International Organization for Standardization (ISO) Standards 14523 and 10214. Storage materials should also pass the American National Standards Institute (ANSI) Photographic Activity Test (PAT), or similar standards, to ensure archival quality. If a photograph exhibits flaking or chipping emulsion it should not be stored in a plastic enclosure as static electricity could further damage the image. Clean cotton gloves should be worn when handling photographs to prevent skin oils and salts from damaging the surfaces.

In some cases it may be necessary to contact a professional conservator. In the United States, the American Institute for Conservation of Historic and Artistic Works (AIC) provides a Find a Conservator tool that helps identify local conservation services. In the United Kingdom and Ireland, the Conservation Register provides a similar tool that searches by specialization, business, and surname. To locate other conservation services internationally, Conservation OnLine (CoOL) Resources for Conservation Professionals provides a tool that searches by country.