Watercolors in the Tropics


PFG, Picture Framing God
Jul 10, 1999
Howards retired
One of my artist friends needs to send a framed watercolor painted on 300 lb paper. She wants to make sure that there are no issues with humidity causing warpage and the like. It isn't framed yet, so she wants to make sure that what goes in to the package is the best to use. The place where it is to be installed has no air conditioning (except what Nicaragua comes with naturally). Any suggestions?
Sealed frame package. Let it live in that temperate Maryland climate all its life.

The only compromise with the sealed frame in this instance is that you'll probably want to use acrylic glazing (shipping concerns), and that is not totally gas impermeable. You might want to include a dessicant panel in the framing to mitigate any breach of the seal.

Short of that you'll have to deal with the humidity (assuming tropical rain forest conditions). Cockling is probably the least of your worries if they are indeed in a rain forest. I would guess that you'll get mold growing pretty quickly.

If they are going to be in the central part of the country, in the high plains or mountainous regions, the weather is much drier and cooler so humidity isn't as big an issue.
Your clients demands create a dilemma: shipping
and climate control. A completely sealed package,
which could slow changes in the paper in that
climate, requires glass and shipping glass in a
frame to Central America is not wise. A sealed
package made with acrylic sheet would slowly allow
moisture to come in through the acrylic and it
would become too damp, inside. Laminated glass
is quite expensive and it could still break.
This is a case in which you are being asked to do
more than can be safely done.

It's not Nicaragua, but close.

When I was in Costa Rica, I saw many lovely watercolors.

I didn't see any exhibiting the dreaded "cockling" or the greatly feared "MOLD"....

Or host said that his mother had collected them from all over Central and North America during the 50s and 60s...
and the framing showed it.... I was a gracious guest and didn't point out the mat burns....

But what interested me was that we were in a steam box about 5km from the eastern rain forest. And no problems.

So I guess my question would be:

If you put real glass, achieve a sealed condition and put a packet or six of desicant and zeolite in the sealed packet....
What happens after the desicant becomes supersaturated? It's not like a bathroom that eventually gets aired out.
If it is a truly sealed system, the desiccant will not become saturated. In semi sealed situations the gel needs to be changed periodically. There are formulas for how much to use/volume of air;some are made to change color when they are saturated. If packaging permits, silica gels can be "recharged" by heating them to drive out stored moisture. They can also act as a moisture sinks - absorbing and releasing moisture according to ambient conditions.

Zeolites can be engineered to absorb and "lock" moisture and gaseous pollutants. Artcare is engineered to absorb pollutants, not moisture. It will not release them. When it is exhausted, it needs to be changed. It does not change color when it is exhausted, but is supposed to last many years in normal framing conditions. there are also zeolites that are designed to absorb and lock moisture.

I have treated pieces that became mold damaged after 6 months in Jakarta, in unsealed frames.