Monsoon Season and Your Artwork

Monsoon season officially runs from June 15 to September 30 here, and it is the biggest environmental event of the year for anything hanging on your walls.

Almost nobody connects the two, so let me.

What actually changes

For most of the year we live in remarkably dry air. Phoenix averages around 51 percent humidity first thing in the morning and about 23 percent by five in the afternoon, and spring runs drier still.

Then the monsoon arrives and the moisture in the air climbs, sometimes dramatically and sometimes for days at a stretch. The record dew point here is 79 degrees, which is a genuinely tropical number in a place that spends most of the year closer to a desert reading.

That is the largest sustained humidity change your house sees all year, and it happens over a few weeks.

Why the swing matters more than the number

Conservation guidance puts the comfortable range for a painting on canvas somewhere between 40 and 60 percent relative humidity, and it is quite specific that fluctuation is more damaging than a steady reading outside the range.

A canvas takes on and gives up moisture. It loosens as humidity rises and tightens as it falls. The paint and ground layers sitting on it do not respond at the same rate, and it is that difference that eventually produces fine cracking.

A steady dry house is easier on a painting than a house that swings, and monsoon is our biggest swing.

What to actually do about it

Honestly, less than you would think, and none of it is dramatic.

Keep the house steady. Running the air conditioning through monsoon does more for your paintings than any specific intervention, because air conditioning removes moisture as it cools, and steady is the whole goal.

Do not open the house up for days at a time during a humid stretch, however lovely the temperature feels after a storm. That is when the swing gets into the walls.

And be a little careful about exterior walls and rooms that are not conditioned. A casita, a converted garage, an enclosed patio room. Those are where humidity actually lands.

What to watch for after

Once things dry out in October, walk your walls in daylight and look at each piece properly.

You are looking for a canvas that has gone slack, and for any lifting or flaking at edges and corners. Both are normal seasonal behavior and neither is usually a problem in itself.

Here is the important part. If a canvas seems loose in October, leave it alone. Tightening the stretcher keys while the air is dry means that when moisture returns next July the canvas pulls far harder than it was built to, and that is one of the most common ways a perfectly healthy painting ends up cracked. It is always done with good intentions.

And the obvious one

Monsoon means water. Check that nothing is hanging under a roof penetration, a skylight, or a spot that has ever leaked before, because the one thing worse than a humidity swing is a drip.

If you ever have a concern about a piece of mine, just write to me. I would rather look at a photograph and tell you it is fine than have you worry about it until October.

Warmly,

Dani