Collections maintenance (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.

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 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 (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.

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Wikipedia