Humidity is one of the greatest enemies of artworks, books and archives. But do you know why?
A large amount of water vapour in the air can act as a trigger for the appearance of fungi and mould, which feed on organic matter. In other words, works on paper, canvas and wood supports are among the most susceptible to these organisms which, if not quickly brought under control, cause irreversible damage.
Mould reproduces by means of microscopic spores that can spread easily through the air. For this reason, one of the most efficient ways of fighting it is simply to prevent it from appearing, by controlling the conditions of the environment.
The ideal humidity for artworks
The space where the collection is kept should have a relative humidity of between 45% and 55% – this is the range considered ideal by museums all over the world. To give an idea, in summer the relative humidity of the air in the city of São Paulo can easily exceed 80% on rainy days. On the annual average, it stands at around 70%.
Consistency is also important, since variation in humidity over the course of the year causes physical changes in the pieces. Canvases can expand when humidity is high and contract when it falls. These are millimetric changes, but they affect the surface of the painting and can lead to craquelure and loss of material. In the case of metal sculptures, the risk is corrosion and, in the case of paper, yellowing can occur.
In many cases, the damage requires expensive restoration work, when it does not prove impossible to reverse. In other words, uncontrolled humidity can negatively affect the market value of an artwork.
What to do to protect the collection from humidity
The relative humidity of the air works inversely to the temperature of the environment – the greater the heat, the lower the relative humidity, and the opposite in cold weather. In general, keeping the temperature of the environment constant, by means of a good climate control system, considerably improves the conservation conditions of the artwork.
Avoiding placing the pieces under direct light or on walls that are in contact with the outside environment are also good safety measures. It is also important to observe whether the artwork is exposed to any source of temperature change, such as ventilation ducts or fireplaces.
Artworks in storage deserve the same treatment as artworks on display – which is a challenge, since it is not always possible to maintain at home or at the company an environment with controlled conditions to ensure safe storage.
If this is the case, the safest option for the collector is to make use of private fine art storage. In Brazil, Clé Reserva Contemporânea is the only company that offers 100% climate-controlled storage, today serving some of the country's most important museums. Discover our services.
