Arid

This climate is generally very dry, however in arid areas it is often very hot during the day and very cold at night. This wide fluctuation in temperature is matched by wide fluctuations in relative humidity, for example from 75%–20% in a day.

When caring for paintings in an arid climate it is important to note:

• Many of the materials that make up paintings will tend to give out the water they contain—this can lead to components of the paintings becoming dry and brittle;

• The composite nature of paintings means that they are particularly susceptible to damage from fluctuations in temperature and relative humidity. As the different materials release moisture at different rates, warping, dimensional change and delamination of layers of the painting structure can result;

• Remember that even arid areas can have periods of higher relative humidity—even though the periods may only be very short. High humidities will cause swelling of some materials, and will increase the likelihood of insect and mould attack;

• Dust can be a major problem for paintings in an arid climate. It is important that paintings are glazed if dust is a problem; and

• For particularly sensitive, reactive works you may consider placing RH buffered fabric or silica gel cells into the framing structure. You will need to discuss this with a conservator.

Note: If your collections of paintings have been kept in an arid environment for a considerable period and they are stable—do not try to alter the environment to meet the recommended ideal conditions. This could do more harm than good. The emphasis should be on long term stability.

Temperature

A temperature climate is considered a moderate climate, however, temperate climates tend to have a greater range of temperatures than tropical climates and may include extreme climatic variations.

• If you redecorating or designing storage and display areas, consider using materials that will help to buffer these areas against rapid fluctuations and extremes or relative humidity and temperature. This will help to reduce the risk of damage due to the fluctuations and extremes that occur in temperate environments.

• Remember that many of Australia's main cities and major regional centre are in temperate regions. These areas tend to be heavily polluted and this should be taken into account.

• Salt laden winds and dust can be problems in many urban and rural areas in temperate zones.

Note: If your collections of paintings have been kept in a temperate environment for a considerable period and they are stable—do not try to alter the environment to meet the recommended ideal conditions. This could do more harm than good. The emphasis should be on long term stability.

Tropical

These climates are characterised by heavy rainfall, high humidity and high temperatures.

When caring for paintings in tropical climates it is important to note that:

• insects and moulds thrive and reproduce readily;

• chemical deterioration reactions generally proceed faster at higher temperatures;

• materials that have been in a tropical environment for some time will have a high moisture content If they are suddenly moved into a drier environment they are likely to suffer shrinkage and warping of the support and stretcher;

• many of the materials which make up paintings are very reactive to changes in relative humidity. For example the animal skin glue used as the size will soften; a wooden stretcher may warp, etc.; and

• composite works such as collage will be particularly vulnerable.

Controlling moisture is important in a tropical environment.

Condensation may be a problem for glazed works and you may need to consider providing air holes in the backing board to allow adequate air flow. Cover these air holes with gauze to prevent insect entry.

Ensure that your storage and display spaces have good air flow.

For particularly moisture sensitive works you may consider placing RH buffered fabric or silica gel cells within the frame. You will need to discuss this with a conservator.

Note: If your collections of paintings have been kept in a tropical environment for a considerable period and they are stable—do not try to alter the environment to meet the recommended ideal conditions. This could do more harm than good. The emphasis should be on long term stability.