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ASK MRS. BIDDINGTONS Advice on Protecting Fine Objects from Heat and Humidity height=

Advice on Avoiding Humidity and Heat Damage
to Antiques and Artworks

Dear Mrs. Biddington,

This summer's heat and humidity are wearing me down. I have recently begun collecting books, prints and other works on paper. The past few days, when I walk into my library, it smells musty.

Could this lousy weather be harming my collection?

Jay Roselle

Dear Mrs. Biddington,

Summers here are always hot, but it's never been so muggy.

My oriental carpets are wrinkled and the canvas of my paintings seems to be sagging. Will these go back to normal? Is there anything I can do?

CiCi Fernandez

Dear Jay and Cici,

It has been a most uncomfortable summer for many of us. Our artworks and fine objects are suffering, too. As the saying goes: It's not the heat; it's the humidity.

Jay, in the case of your books and prints, the paper is absorbing a great deal of moisture from the surrounding air. That's the source of the dank, musty smell. High relative humidity can promote the growth of mold on paper. You may have seen prints with small brownish dots. This is mold growth called foxing.

Cici, the fibers of your rugs and painting canvases are expanding. In the rugs, warp & woof threads are not expanding at the same rate; the result is a wrinkling. The paintings canvas sags a bit because its expansion has caused it to be larger than its wooden stretcher (which also is expanding but to a lesser degree).

Come autumn, the musty scent will mostly abate and the rug and paintings will mostly return to their prior forms. But this summer's weather did not enhance their state of preservation.

Many people return home at the end of a working day to a sweltering house or apartment and immediately turn the air-conditioner to maximum cool. Both temperature and humidity drop precipitously in a very short period of time. (Just thinking of this stiffens my neck.)

You needn't be a museum conservation expert to understand that these abrupt humidity and temperature changes have a deleterious effect on your artworks and valuable items. Over time, all this expansion and contraction weakens fundamental materials. The uneven "breathing" causes a break in the adhesion between different types of materials. The result can be paint flaking off canvas, veneer peeling off furniture, even glazing chipping off pottery.

Controlling humidity is the most important step in seriously caring for valuable objects. Nearly all antiques, collectibles and works of art are happiest at a relative humidity in the neighborhood of 50% . (Temperature is a considerably less important factor so long as it does not vary enormously within a short period of time.)

So, for very sticky summer weather, a dehumidifier or air conditioner set at a constant, moderate temperature is very helpful to the long-term conservation of your valuables.

For the well-being of works on paper and other items hanging on walls, it is desirable to mount them so that some air circulates behind the object. Anything that helps air circulate gently is useful. The lazy rotating of a ceiling fan works nicely.

In my girlhood, we followed the custom of rolling up thick rugs and storing them in a cool, dry spot for the summer--a most sensible tradition for any heavy textile.

As with fine wines and vintage humans, antiques and artworks benefit from a stable, moderate environment. Still, none of us is going to endure forever. Undertake whatever conservation precautions you can conveniently perform and enjoy us while we last.

Augusta Biddington

Ask Mrs. Biddington Archives:
Ask Mrs. B--Framing and Hanging Paintings
Ask Mrs. B--Cleaning Paintings & Works on Paper
Ask Mrs. B--Framing Prints & Works on Paper
Ask Mrs. B--Lace Restoration
Ask Mrs. B--Lace Cleaning
Ask Mrs. B--Liquidating an Estate
Ask Mrs. B--Humidity & Fine Objects
Ask Mrs. B--Roseville and Removing Spray Paint
Ask Mrs. B--Care of Doll Hair


The thrill of the auction is over--for the moment. With art & antiques, pleasure also comes from acquiring the specialized knowledge involved in their preservation. Even experienced collectors may not know exactly how to care for fine art. At BIDDINGTON'S, upmarket, online art auctions & art gallery, our in-house oracle on fine art preservation and restoration procedures is Augusta Biddington. Mrs. Biddington is an old hand at old things. Unfortunately, This archived feature was first published in 1999. Mrs. Biddington is no longer able to provide answers to specific questions.

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