White bread, raw garlic, onions and potatoes may sound alright if you're hungry, but some people believe that they can clean oil paintings with them. Their reasoning is sound enough: Each of these foods has the right amount of moisture in them to pick up water-soluble dirt without getting the picture wet. However, the foods also leave behind various kinds of bacterial residue, which begin to eat away at both the paint and the canvas.
Another bit of "kitchen chemistry" down the drain. Still, it has its adherents, as do a number of other home-grown ideas about how to care for one's art collection.
Some people believe that, since oil and water don't mix, one may clean an oil painting with soap and warm water. Again, it sounds like it should be okay, but it's not. Soap generally comes in a concentrated form and can damage the paint or diminish the value of the colors. The water will likely squeeze through the cracks, which oil paint inevitably develops, and go all the way back to the canvas. The water then makes the canvas expand, then contract, as it dries, and this process loosens the bond between the paint and the canvas, which may result in the paint flaking off.
One technique that Vincent van Gogh and many other artists have used with their drawings and prints is to pour milk on them. "Milk has casein as its base, which is an adhesive," said Lucy Belloli, a conservator at the Metropolitan Museum of Art in New York City. "The milk fixes the ink or pencil on the paper and makes the colors more intense. The only problem with it is that milk becomes brittle in time and the paper, which is more flexible and will expand and contract, might damage the milk coating."
"There's no magic elixir or special potions for taking care of works of art," said Perry Huston, a private art conservator in Houston, Texas. "However, it does take judgement and experience and years of training one's eye. You can't just decide to clean or repair a work of art and think that you don't need any professional help. People like myself are trained for many years to know what to do and how it should be done."
Huston's favorite wive's tale about taking care of pictures is the holes-in-the-backing technique. Many people cut holes into the backings of artworks because they are aware that paintings need to "breathe" -- that is, expand and contract with climatic changes in heat and humidity. However, these holes allow dirt and grime to enter, which the backing is put on to protect against.
"For my money, it's better to keep the dirt out than to worry about whether the painting is 'breathing,'" he said. "All I've ever found that the holes do is let the accumulating dirt breathe."
Cleaning works is where most people get into trouble. Randolph Jones, Jr., a painting restorer in Memphis, Tennessee, noted that some of his clients had attempted to apply cold creme to their works in order to cleanse and moisturize their surface. Not illogically, they attribute a painting's dryness to a lack of moisture, "and they pour oil on it, but all that does is to rot the canvas supports," he said. One cannot remoisturize oil paint.
Other conservators also complained about customers bringing in paintings that had been treated by their owners with linseed oil, poppy seed oil, sesame seed oil, even motor oil -- substances that often stick to the painting and make them almost impossible to clean in the future.
Another seemingly logical but ultimately destructive cleaning method is vacuuming, which will suck dirt from the back of the canvas, but may also make an indentation in the canvas, especially if it is dry. It can also pull off looser bits of paint. Use a feather duster at most, conservators recommend.
People will occasionally attempt to clean photographs with a pencil eraser in order to get dirt off the face of a print -- which has the result of abrading the surface and leaving a permanent mark on it -- or washing it in water. The problem with water is that it may act to wash away some of the stabilizing agents that fix the image and tones of the print. If there is any ink on the back of the photograph, for instance, a rubber stamp or penned notation, that color may be activated by the water and migrate through to the front of the print.
Henry Wilhelm, a photography conservator in Grinnell, Iowa, said that "the best thing to use is Kodak film cleaner and, if that doesn't work, give up. But, really, you're safest by doing nothing or going to a trained conservator. Once you've wrecked a photograph, it's through and can never be restored."
Conservation is a slow, painstaking job of testing and cleaning small areas of a picture at a time. Each color in a painting has a different solubility. Whereas a cleansing may work well on one color, it may completely wip out another, and this is why conservators never work on the surface of a work of art with any tool whose head is larger than a cotton swab. A large part of the conservator's job is testing the surface of the work to determine exactly what is there. They often find overpaint (tourch-ups that some restorer has done) and some form of varnish or other coating, such as polyurethane or shellac, as well as surface dirt and cigarette smoke. All of these elements need to be removed chemically before the work can be cleaned, and the cleaning may involve working separately on different layers of paint, the primer and the canvas itself.
Still, do-it-yourselfers try their hand and at great risk to their valued art possessions. The more knowledgeable of them attempt to use materials that do have a place in art conservation, such as alcohol or bicarbonate or soda, but they do so in such a broad and indiscrimate manner as to damage more areas of the artwork than they conserve.
Some may use solvents that the art conservation field has long since abandoned, such as benzene and carbon tetrachloride, which are proven carcinogens, or caustic soda (otherwise known as lye). Barbara Heller, head of painting conservation at the Detroit Institute of Art, said that caustic soda "cleans great, because it eats through dirt and old varnish, it also eats through everything else. No one can stop it."
Randolph Jones, Jr. noted that one of his clients, who had done some reading in art conservation, concocted her own cleaning solution, using alcohol, mineral spirits and other chemical ingredients, to restore a portrait of one of her ancestors, which had belonged to her family for generations. "It took the varnish off, sure, but it took off everything else, besides. She completely obliterated the face." It was at this point that she brought the portrait to Jones.
"I can work miracles, but I can't restore what I can't see," he said, adding that the client had been searching for old photographs of either the painting or the ancestor for Jones to copy in redoing the portrait.
Those who are less knowledgeable conceive their own ways of unintentionally damaging their artworks. Noting that "people consider objects not as valuable as paintings," Carolyn Rose, director of the Anthropology Conservation Laboratory at the Smithsonian Institution in Washington, D.C., said that many collectors tend to "treat objects as they do their utilitarian objects at home. For instance, they see a stain on a textile piece and try to get it out in the washing machine. Then, they're all surprised when it comes out all shredded."
She also complained that these collectors will try lemon juice to clean a spot. Because of its high acidity, lemon juice tends to eat through the fabric. They might put baking soda or vinegar on a diamond ring, which will clean it but leave behind a residue that causes corrosion and attracts the glues holding the settings.
If a portion of a sculpture breaks, she said, many people will attempt to repair with with a drug store epoxy or Super-Glue. These generally do hold the work together, but often the adhesive is stronger than the material of the sculpture itself. Just like a painting canvas, a wooden sculpture needs to breathe (expand and contract), but the epoxy won't. This creates tensions elsewhere in the piece and may result in future breaks.
In addition, owners of wood sculptures may look at protect their objects from the elements by coating them with some household wax or varnish. It's a nice idea, but this may act to change the object's color and surface texture as we as create an impermeable moisture barrier that won't allow the work to breath.
The history of conservation is filled with tales of disaster and folly. Up until the middle of the 20th century, restorers regularly repainted sections of the work the Old Masters in order to satisfy the then current notions about what constitutes good taste. It reflected what now seem like rather cavalier attitudes about how artworks should be repaid, the price of which has been the deterioration of many priceless objects. For art buyers, the less restoration that has taken place with a work, the higher the price is likely to be. Conservators are more careful now, not withing to do anything that cannot be undone by the next conservator. Today's horror stories are largely due to art owners who believe that they don't need conservators and can fix very subtle and complex problems by themselves. The more money they try to save, the more they will have to pay later when the work needs to be salvaged.
"Eventually, it all comes back to haunt them when the objects start falling apart," Rose said. "There's no getting away from the kind of care that a conservator can provide."
Postscript:
I am one of the speakers in a career-oriented online workshop for fine artists. Those who might be interested in listening to what I and others in the field of artist career development have to say may register here.