THE SHOWCASE ENVIRONMENT

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Objects on display may deteriorate if the right conditions are not maintained within the showcase and gallery.
The major causes of damage are:

  • Variation and extremes of temperature and humidity
  • Chemical pollution
  • Inappropriate lighting
Construction Materials and Finishes

Inert materials such as glass, aluminium and steel are suitable for showcase construction.
Timber based products such as MDF may not be suitable for in case use unless treated to prevent the off gassing of formaldehyde and other chemical pollutants. Treatments include the use of acrylic sealants, melinex and aluminium barrier films. These should be applied to zero formaldehyde
MDF (ZFMDF)

Fabrics - a number of natural and synthetic fabrics are generally suitable for internal case finishes and are bonded using a water based adhesive or are stapled. It can be the dye rather than the fabric which will cause problems and fabric colours should be tested to establish their suitability.
Time must be allowed for testing and the possibility of having to find and test alternatives.

Paints - a range of acrylic water based paints are available which can be safely used within the display chamber.

Relative Humidity
Fluctuations in relative humidity can be actively buffered by the use of preconditioned Artsorb™ silica gel.
Artsorb™ silica gel buffers the RH within the case which must first be brought to the correct level. Buffering works best where there is minimal air change and the gallery environment is relatively stable and similar to the case.
More difficult gallery conditions may require the use of a humidity control unit which can serve a number of cases sharing the same micro-climate. In this situation the air can be circulated through the cases or a positive pressure applied which leaks air out through the showcase seals.

Heat build up
Showcases should be located away from sources of heat such as sunlight and radiators, additionally heat generating lighting components should be mounted away from the display chamber and ventilation fans used.

Air Contamination
Contaminants in the air and those given off by the objects can be neutralised by incorporating materials such as activated charcoal cloth in the case construction or within the
humidity control unit.

Air Change
A key factor in maintaining the internal case environment is the rate at which air is exchanged between the case and the gallery. This air change can be beneficial where objects themselves give off harmful substances but for most purposes a minimal air change rate is desirable.
To achieve this the case is sealed at all fixed glass and other joints with a neutral curling silicone and a compressed seal is used around doors.
A stable temperature within the gallery helps to minimise the breathing effect thus reducing the air change rate.

Further Information
The information above is intended as a general guide to current practices. Conservators should be consulted as to the particular requirements of the objects to be displayed.