Protecting works of art

Protecting works of art is complex and delicate.
The key lies in “preventive protection”, which means effectively monitoring the environment in which works of art are stored to achieve a stable environment with constant temperature and humidity, as well as a clean environment that limits dust.

The display and storage of works of art is complex due to their rarity, their extremely precious nature and their almost equal sensitivity to the impact of air. Some historical works come down to us today, such as inscriptions, pieces of buildings, tools, coins, utensils of life and various works of art.
It’s because they were generally stored in a particular way (buried, etc.), or even discovered recently, that they have been able to survive these “many years” and reach us.

What impact does air have on artwork?

Specific events usually include the following:

Corrosive pollution caused by impure ambient air (pollution ) ;
Physical damage caused by low or high ambient temperature and humidity ;
Irreversible, permanent damage caused by severe fluctuations in ambient temperature and humidity.

Therefore, whether it’s a museum, a temporary exhibition room, a personal art collection or a private art collection, the collection storage environment must be strictly controlled to provide an optimum environment for the collection.
Whatever method is used, the temperature and humidity of the ambient air must be adjusted to suit the different storage requirements of the collection.

Combining public impact and art preservation

What kind of climatic treatment should be used to preserve the works?

It’s difficult to reconcile the thermal comfort of visitors and the preservation of works of art: just as people need an appropriate temperature and good air quality, works of art also need a specific environment to be preserved intact.

For museums, air-conditioning temperatures are not decided at random by the HVAC manager, and climate control is generally not carried out for the well-being of tourists.
Although this answer may seem self-explanatory, defining temperature is also complicated, as works of different textures, materials and years of creation may have different temperature requirements.

To protect these historic works of art, the temperature in the exhibition halls can be controlled at 18°C-22°C all year round, or the works can be displayed in air-conditioned showcases. Maintaining good climatic conditions in museums is therefore a complex task.

Different climatic environments for each work

Specific climatic conditions to be maintained for each work

For example, the natural fibers such as wood, paper, cotton, linen and silk commonly used in ancient paintings and calligraphy generally have stricter temperature requirements.
High temperatures can lead to condensation and swelling of the work, while low temperatures can cause the material to crack or wrinkle.

In contemporary art, some conceptual and experimental works will be recycled or destroyed according to the artist’s ideas after being exhibited, so temperature control is not necessary.
Others rely directly on the air movements of the exhibition room to transcend these generally masked systems.

Relative humidity management for the preservation of works of art

In addition to temperature, relative humidity (RH) also has a very important impact on the collection, especially the specific humidity in a particular area of the space.
If RH is too high, fungus and mildewcan develop; linen and silk fabrics discolor easily; metalwork such as copper and iron is easy to rust or corrode.
If relative humidity is too low, oil paint mounted on wooden frames can cause surface cracks due to deformation of the wooden backing board.

In this context, since temperature leads to changes in relative humidity, international temperature and humidity standards for museums and art galleries are generally formulated according to precise norms.

Overall, the indoor relative humidity should be between 45% and 55%, each allowing a 5% variation, preferably between 40% and 60%; the temperature range should be between 18°C and 22°C.
More specific parameters may be required for specific works.

Of course, these values are not absolute.
There is a further explanation for this; i.e., some works have to be adjusted to the actual situation by inspection, and the requirements for storage conditions for works on loan have to be finalized after consultation with the curators.

Daily temperature oscillation

Another very important point is to minimize sudden fluctuations in these parameters.
Regardless of temperature and humidity, a sudden increase or decrease can cause irreversible damage to collections.

Thermal inertia is generally better in older buildings, and climatic stability is easier to control with light means than in newer buildings with lots of glazing.

A room opening to the outside will be subject to considerable climatic variations and should be preceded by an airlock.
For any type of building, doors or windows should never be opened indiscriminately when the ambient conditions outside and inside are very different.
CFD simulation can be used to analyze the impact of opening exterior doors when installing new works.

The influence of temporary exhibitions with an excess of visitors must be taken into account in the use of exhibition halls.

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Louvre Paris - Escalier de la victoire de Samothrace - Thermal comfort study

Impact of dust

Ambient air carries gases, dust and micro-organisms which are deposited on and in works of art.
Dust is a highly penetrating particle that is the cause of much damage. In the open air, it is difficult, if not impossible, to eliminate the dust generated by the degradation of materials and carried by visitors.
Here, it’s the stability of air movements that’s important.
Over time, dust is deposited in the gallery’s various dead zones, and the movement of air by the creation of draughts (door openings, for example) is likely to loosen the layers of dust that are inaccessible to maintenance and have accumulated over time, thus contributing to the pollution of the works.

Optimizing climatic parameters using CFD simulation

We study the implementation of climatic conditions as a whole in order to guarantee optimal preservation of works of art.
We carry out CFD simulations to inform curators of the various impacts caused by poor climate control.