I’m asked all the time something along the lines of “What is the best temperature for my artwork?” or “What temperature should my house be?” or “What environment is best for my collection?” Well, its not a one word answer. The answer is kind of long, actually, but I think you’ll find the answer and the photos interesting.
What materials are you worried about protecting? A wood sculpture, an oil painting, a watercolor, glassware, a plastic toy collection, photographs, leather book bindings? Each material reacts to it environment a little different but by and large the answer to this question is, thankfully, not a single number temperature (that would be hard… and expensive… to try and maintain!). Its a range. My detailed answer to this question would be different for someone in Florida than Wyoming, or for someone living in Puerto Rico or Utah. But in general, what your items need, much like all of us, is stability.
Here are three parts to my answer and tips to help protect and keep well your treasured items:
Tip #1. Keep the temperature within a 20 degree F. range within a 24 hour period. So, for instance, a storage area like a garage or attic where the temperature drops to 40 degrees at night and goes up to 80 degrees during the day is a very poor environment. What happens is that the materials your treasured items are made of are expanding and contracting in those temperature fluctuations. But while temperature seems like the real problem to solve, actually its humidity. As a general rule, items like temperatures that are a little on the cool side for people’s comfort: 55 – 65 degrees. In my house in Southern California I don’t have air conditioning. But we can keep our living space within a 20 degree range (in a 24 hour period) all year long without much effort.
Tip #2. Humidity is the real driving force of dimensional change in your items. I don’t want to get too technical here… but the range of humidity should also be kept within the 20% relative humidity (RH) range within a 24 hour period. This is more difficult to measure and control than temperature. Homes aren’t furnished with a dial on the wall for humidity control. But take a look at the photo below…
Temperature and humidity in our environments, outside weather or inside the home, are tied together. They move and change together. So, whether you live in the extreme of the tropics or the desert, try and limit your temperature to stay within a 20 degree F. range and you’ll probably be doing the best you can do without having to buy humidification or dehumidification equipment.
If your photos are tossed in a box all touching each other, then higher humidity will cause them to stick together (see chapter in book about getting them apart). Wide ranges in change of humidity also cause wood to warp. These are the reasons why many museums will let a crate containing artwork that has arrived, sit in storage all closed up and sealed for at least 48 hours before opening up… so that the item can acclimate to change in temperature and humidity slowly to minimize damage.
Extreme situations, like the tropics may call for dehumidification equipment to minimize mold growth etc. But as a general rule, you now know the best range. If you can control the humidity, a range of around 50% RH is very good. Once more thing…
Tip #3. Damage of an item will be accentuated as fluctuations in temperature and humidity take place. On the photo, look just to the left of the face, just into the white background area. Here’s a close up…
This bullseye cracking pattern (or it looks like a spiderweb) is caused by something having hit the surface. When it occurred, no damage was seen. But the stress on the paint/ground send shock waves, much like dropping a pebble into water. This pattern shows up, more or less severe, when temperature and humidity change a lot, over and over. So, protect your items from damage during handling, storage etc. or you may find problems arising in the future.
One night of temperature outside of the 20 degree range isn’t going to kill your painting. But, depending on the humidity, it may cause cracking in a wood item or photographs to stick together. Its the repeated fluxuations and the abuse the item has taken that result in the visible damage. This damage almost always has an effect on the value. If you have appraisal questions, go to www.faclappraisals.com
I told you it would be kind of a long answer but this is money you can take to the bank.
Questions about art conservation? Call Scott at 805 564 3438
Art appraisal questions? Call Richard at 805 895 5121
Also, see our fun videos on Youtube at http://www.youtube.com/user/PreservationCoach?feature=mhee
Tags: Air conditioning, art conservation, art on paper, art preservation, cracking paint, damage, damaged art, do it your self, Heat, Heater, home treatments, Humidity, Painting, Relative humidity, Shipping, storage, Temperature