Collections maintenance

Visual storage at the Victoria & Albert Museum

Collection maintenance is a form of collections care that consists of the day-to-day hands on care of collections and cultural heritage. The primary goal of collections maintenance is to prevent further decay of cultural heritage by ensuring proper storage and upkeep including performing regular housekeeping of the spaces and objects and monitoring and controlling storage environments. Collections maintenance is closely linked to collections care and collections management. The professionals most influenced by collections maintenance include collection managers, registrars, and archivists.

Environmental Control

There are four main environmental agents of deterioration which should be monitored on a regular basis as part of maintenance. These are temperature, relative humidity, light and dust. It is important to recognize the type of damage each agent may present as well as ways to mitigate any harm.

Temperature

Temperature as an agent of deterioration acts primarily in conjunction with relative humidity but can trigger damage in its own right. At the extremes, temperature can cause structural damage to some materials; paint may become brittle in excessive heat and some plastics may soften or melt in the heat. “High temperatures also accelerate chemical and biological processes.”

Relative Humidity

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A thermo-hygrograph

Relative Humidity (RH) is the amount of water held in the air as related to how much could be held in fully saturated air. The possible amount of moisture held at a given time is directly related to temperature; warm air holds more humidity than cold. Collecting institutions aim to keep the RH constant in exhibitions and storage areas because many organic objects expand and contract as both temperature and RH change. Furniture will swell and stick with high moisture, but may crack or shrink if there is too little. “Rapidly fluctuating temperature and relative humidity compound all of these effects.” High humidity may accelerate mold growth and some chemical changes, like metal corrosion, if not properly maintained.

Some changes undergone by objects are reversible by adjusting the RH, but damage like cracks are more permanent. Keeping the RH within a reasonable span for the type of object and as consistent as possible will prevent most RH based damage. It is important to measure the RH of spaces regularly by using a number of tools including humidity strips, thermo-hygrographs, hygrometers, psychrometer and data loggers. Once the per cent humidity identified, there are a number of ways to adjust it by using humidifiers, dehumidifiers, improve heating and air conditioning systems and adjust the temperature of the space.

Light

Light, as it relates to collections maintenance, consists of visual and ultraviolet light (UV). Both types of light can cause damage as “light radiation falling on a surface provides energy to induce chemical changes in the molecules of the material.” Damage from light, including loss of color and strength, is cumulative and irreversible. It is therefore crucial that light levels are monitored.

Preventing light damage is difficult because it is necessary for visitors as well as people who are working with the objects. Exposure, however, can be diminished by ensuring lights are only on when people are present, either by vigilant staff members turning on and off lights, timer switches or with motion sensors. Natural light from windows should be reduced or eliminated in all spaces by covering them with curtains, shades or UV absorbing filters. Where lights frequently on, like in galleries and office areas, a light meter should be used to determine how much exposure the collections are getting at least once a year and adjustments should be made accordingly.

Dust and Dirt

Dust can contain a number of materials including skin, mold and inorganic fragments like silica or sulfur. It is important to keep collections free of dust whenever possible because it can become bound to a surface over time, making it that significantly more difficult to remove. Dust is hygroscopic, meaning it is able to attract and hold water molecules creating an ideal climate for mold spores to grow and cause biological damage. This hygroscopic trait can also prompt chemical reactions on a surface, especially upon metals. Inorganic dust particles may have tough sharp edges which can cause a number of types of damage from tearing fibers to abrading softer surfaces if not properly removed. Wiping a clean cloth over a surface dusty with these inorganic particles may result in irreversible abrasions.

The best way to prevent damage from dust is to control and prevent substantial buildup of dust in the first place. This can be done by using air filters in the heating and air conditioning systems as well as using vacuum cleaners equipped with HEPA filters when possible. Limiting the amount of exposed surface areas of collections can also prevent dust from settling on objects. This can be done by storing objects in acid-free boxes, object specific enclosures, in drawers or covering open shelves with a polyethylene sheet.

Storage and Upkeep

Maintaining a clean and orderly spaces ensures not only ease of accessibility but also the safety of the collections and those who work with them.

Organization

Example of two "layers;" the boxes and the shelves they rest upon

It is essential that collections have an organizational system to store and house objects. The system may be grounded in relations to size, material, cultural or historical grouping as it makes sense to the collection. Structured organizational systems make identifying object locations straightforward and consistent which will help locating and returning an object to its proper space.

Part of a system is the use of “successive layers of protective envelopes and enclosures.” Types of “layers” include nearly everything from storage spaces, padded shelves, non-acidic archival boxes and individual packaging. Each new layer should provide further protection by creating a microclimate buffer between an object and environmental fluctuations, light, dust and pollutants.

Housekeeping

Keeping spaces clean and clear of debris is crucial to the preservation of object in several ways. Primarily it ensures that objects don’t become over exposed to detrimental agents like dust, but it also ensures that the areas are safe for people and objects to move within, unobstructed by potential hazards. Tasks that fall under this purview include routine inspection and dusting of work areas and objects, and general cleaning of work areas. Spaces and objects should be monitored and inspected regularly to ensure that any problem is caught and resolved quickly or note any condition change.

The regularity of dusting and cleaning will differ institution to institution, and will depend upon factors like foot-traffic, how well the space is sealed off from the outside, and how long it takes for dust to build up. As a general rule, work areas should be cleaned frequently, storage areas and furniture less so, and objects dusted occasionally and only after consulting a conservator. Inside work areas, floors should be swept or vacuumed and work surfaces should be cleared off and dusted. Storage areas probably need less frequent attention, but should still have the floors cleaned and exposed surfaces of storage furniture like shelves wiped down. Objects themselves may sometimes need dusting if they are not boxed or wrapped up. Prior to dusting an object, the condition and stability needs to be considered, and a conservator should be consulted before any attempt is made. Research should also be done into how best to clean a particular type of medium or object.

External links

• Collection Maintenance
• NDCC Monitoring Temperature and Relative Humidity
• National Park Service Museum Handbook
• National Park Service Conserve O Grams
• Connecting to Collections Housekeeping Webinar
• Minnesota Historical Society Housekeeping Handbook