The conversation that artists are most likely to enjoy having with buyers concerns what inspired them to create this or that and the ideas they seek to express in their work. Less enjoyable are negotiations over price (how much it costs, if any discounts are available, how they will be paid), and less enjoyable still is a discussion of the type of care that their artwork may require over time. Too often, artists shy away from questions of care, because they themselves may not know much about the materials they are using and how their pieces weather over time (and what, if anything, to do about it) and because they worry that such talk might cause prospective buyers to back out of a purchase.
Phoebe Dent Weil, a retired sculpture conservator at the St. Louis Art Museum who continues to work for private and institutional clients, claims that artists need to look beyond the initial sale to the long-term maintenance of their work. And, they need to talk to buyers about how to keep artworks looking good. “Collectors may get very upset if the sculpture they buy starts to look very different and starts to lose its value,” she said.
Weil herself was called in by the Houston Museum of Fine Arts when a polished carbon steel sculpture in its collection by the Italian artist Pietro Consagra rusted all over. Should the museum sand off the rust and polish the piece, knowing that the rust would recur? She spoke with the artist, who was still alive, recommending that the work be painted, which might make the piece look a bit different but would provide lasting protection. The artist was happy with the recommendation and began incorporating paint into his other steel works. He also was lucky that the conservator the museum chose to contact had an idea about how to keep his work from looking good. That helps the artist’s reputation and keeps the museum interested in his work.
Light, heat, humidity, dirt, dust and especially water are all potentially harmful to works of art, and the damage is dependent upon the materials used and where the objects are located. Artworks placed outdoors are most likely to experience changes through cold, heat, moisture and pollutants, and some materials are better able to weather these changes or be treated than others. Stone sculpture, for instance, is porous and can absorb water vapor up to four inches deep, taking airborne pollutants into its interior. Eventually, when it dries out, the stone will “sweat” out these particles, which creates an erosion on its surface, slowly eliminating some of the detailing.
Bronze, too, reacts badly to humidity, turning green. Weil stated that chlorides in the patina – the surface sheen of an object – occasionally reacts with high humidity to cause “bronze disease,” which is green mold-like spots that start appearing on the surface. She noted that there is not much one can do to permanently stop this condition, although regular cleaning and waxing of the work does provide some protection from the humidity. Wood is most severely affected by moisture in the air, expanding in high humidity and contracting in a dry environment. Two adjoining wooden pieces in an object may expand against each other and knock themselves out of line, and the glue holding pieces together may dry up and cease to bind the parts together. The ideal relative humidity levels are 55 percent for wood, 50 percent for stone and 40 percent for bronze.
Unlike paintings and drawings, wooden sculpture cannot be placed under glass to protect them from strong light. She noted that these pieces should be kept away from windows where direct sunlight would hit them, since their veneer absorbs heat which can lead to cracking.
Certain types of antiques or sculpture are born trouble, no matter what anyone does, Weil claimed. Claes Oldenburg’s outdoor pieces, for instance, are cast in Everdur bronze that has the distinction of tarnishing and discoloring very rapidly. If one touches a piece made in Everdur bronze, the mark must be immediately cleaned off or else the fingerprints may be permanently etched into the metal within a matter of days.
Other problems may have been found with Cor-ten steel, which has been used for works by Alexander Calder, Louise Nevelson, Pablo Picasso and many other artists. Cor-ten was thought to be an answer to outdoor environmental conditions as it formed a tight oxidation layer that stabilizes and acts as a buffer against further corrosion. Weil stated that there have been serious problems when conservators seek to clean graffiti off works made of this metal. “To clean it, you have to remove the entire rust layer. Then, another rust layer has to develop.” The result is the removal of actual metal, which may change the proportions and appearance of the entire work.
Artists, of course, choose the materials they use often for other reasons than longevity. Picasso would not have pasted newsprint onto some of his late Cubist canvases had his concerns been the problems conservators would face decades later. As a result, artists should provide guidance to their buyers in the maintenance of their work. Here are some Don’ts that Weil has to offer:
- Don’t use Pledge on a wood sculpture. It may leave residue, cause discoloration and provide moisture that enters the wood.
- Don’t use Brasso metal polish on metal sculptures. It has a mild abrasive and leaves a residue of white powder that collects in corners.
- Don’t use a rag to remove dirt and dust. The rag may catch on sharp points and abrade the surface. Feather dusters are better but are more difficult to control. Instead, use a soft bristle paint brush, taping the metal ferule to guard against scrapes.
- Don’t put a waterproof coating on stone sculpture. Rainwater will get underneath the coating through cracks and cause the coating to chip off, distorting the overall look of the piece.
And, of course, what one might expect from a conservator: If a buyer has questions about how to protect a work from damage or restore a piece after damage has occurred, contact a qualified conservator.
By Daniel Grant