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Water & High Levels of Humidity: A Painting’s Worst Enemy!

July 23, 2019

Today, many of us have faced the consequences of torrential rain and flooding.  It is becoming more common to hear about areas of the country that are under water, houses flooding, and personal property being damaged or destroyed.  I have even experienced this when Sandy hit the Northeast and flooded homes in our neighborhood – ours included.  When the water receded, we found that two paintings (which were sitting on the floor in the lower level of our home) suffered water damage.  Luckily, we had insurance for our artwork.

While searching the internet for information about water damage, I discovered there is very little out there … certain conservation and restoration services have short articles, and The American Institute for Conservation’s (AIC) website has a general article on Caring For Paintings (https://f9f7df2c79cc13143598-609f7062990e04dd7dd5b501c851683c.ssl.cf2.rackcdn.com/aichaw_0493f1d82de26310c50cab7af5c54d87.pdf)  This article will attempt to give you a better understanding of what damage water and high levels of humidity can cause.

To begin with, you need to understand the actual make-up of an oil painting, and I am going to limit myself to older works of art for this discussion.  Initially, the artist needs to choose a support – canvas stretched on a wooden stretcher, flat wood panel, canvas board, etc.  Then, using a brush, they prime the support with gesso (a white paint ground) in order to create a stiffer and smoother base coat to paint on.  This layer of gesso also prevents the oil paint from being absorbed by, and possibly damaging, the support.  Once primed, the support is set aside to dry for at least two weeks; at which point it is ready for the final layers of oil paint – the artist’s work of art.

Traditionally, gesso was made from a combination of chalk, white pigment, animal glue and water (used to dilute the mixture; making it easier to apply).  Today, there are other types of gesso available, including acrylic forms, and there are canvases and panels that can be bought already primed. 

Now you would think that once the gesso had dried and was covered with oil paint and varnish, all would be well, but that is just not the case.  The problem is that because the basic support (canvas, wood, etc.) is exposed on the back and porous, water can be absorbed and cause the gesso to reactivate.  If enough water is absorbed, the bond between the oil paint and gesso, or between the support and gesso, can give way causing the paint to lift or flake.

Most conservators will tell you that it is important for works of art to be kept in fairly stable environments; a temperature of 75 degrees and a humidity level of 55% are ideal … but we all know that our homes are less than ideal and temperatures and humidity levels will fluctuate throughout the year.  What everyone needs to understand, is that paintings can and will adapt to minor environmental changes as long as the changes are not sudden and dramatic.

Here is a story about one such sudden and dramatic change in humidity levels – relayed to me by a conservator.  An important Old Master painting had been hanging in a damp castle in Europe all its life (a less than desirable environment to say the least).  When small changes in its condition began to appear, it was decided that the work should be moved to a climate-controlled environment — the results were disastrous.  Once removed from its damp home, the painting began to deteriorate at a rapid pace … the problem was that the painting had acclimated to its original damp environment.  The move had actually caused more damage than it was supposed to prevent, and the painting was returned to its damp home where it stabilized.  The restoration/conservation was then carried out while the work was in its original environment.

Serious levels of water, in an environment that is usually water-free, will have similar effects.  The recent hurricanes and floods in the United States brought disastrous levels of water into homes.  Of course, those works of art that were complete submersed in water were probably destroyed beyond repair … all of the paint would have literally washed off the support.  However, even those works of art that were in homes where the water levels may not have risen above the artwork, many have suffered severe damage.  The reason for this is two-fold.  First, the extreme levels of humidity that was present for an extended period of time would have caused drastic changes in the work’s environment.  These rapid changes in humidity levels could cause the supports to ‘move’… canvases would have loosened up and panels may have cracked.  This, in turn, could cause severe cracking and even flaking of the oil paint.  Second, even though the work itself may not have touched the rising water, the walls on which they were hanging did; absorbing serious amounts of water and likely transferring some of the water to the works of art.  This, in turn, could cause the gesso to reactivate and in some cases, the paint could have fallen off its support.  Now you may think that all of these works are totally destroyed, but that is not always the case.

When I first entered the art business, I spent a year working with a conservator …  we actually owned a conservation studio for more than 20 years.  I remember when a call came in from a collector who was in a panic about a work of art that was hanging in his apartment.  While he was on vacation, a steam pipe broke and there was a painting hanging above it.  When he returned, the entire center section of the painting had loosened up, cracked and fell off the canvas … there was a pile of little pieces on the floor.  The head conservator went over to assess the damage and returned with the severely damaged painting and a baggie filled with all the little pieces that had fallen off.  After carefully conserving the structural support, he was able to piece together (and glue into place) all the pieces from the lost area … thereby restoring the work.  In the end, it was very difficult to even see that the work had sustained such serious damage.

Keep in mind that smaller amounts of water can also cause serious problems.  It is best to always store paintings in the living areas of your home; not in basements or attics where there are both wide fluctuations in temperature and humidity.  If a work of art has been covered by water, the first thing you should do is remove it from the affected area – holding it face up and level.  Then, if the surface looks stable, blot up any excess water with a soft cloth.  Do not wipe the surface – if small areas have begun to lift, you may actually cause the paint to chip off.  As soon as possible, contact a professional art conservator so that they can assess the level of damage and determine what can be done to conserve the work.  You may also want to call your insurance company to inform them of the situation … they may have specific requirements for the loss to be covered.

Now before you panic about collecting works of art because of the potential issues ‘water’ and ‘humidity’ can cause, please remember that most older works of art have survived for decades or centuries in environments that had little or no climate controls.  Many of these works are still in great condition and since the development of central air and heating, they are now living in much safer and more stable environments.

One final comment… it is very important to remember that in the case of a natural disaster, one’s first thought must always be for the safety of human life.  Once that is taken care of, we can worry about personal belongings … though I have told members of my family that if we have to evacuate our home because of a pending flood, make sure there is plenty of room in the cars for the art!