David Covey

Portrait of a Woman had arrived with a murky yellow coat of varnish and with 300 years’ accumulation of dirt.

Gary Alden: “Once the paint is securely affixed to the facing, the backing is removed by scalpel.”

David Covey

The vacuum hot table was ready. The tape was in place, holding the subject flat on the table. From either side, hands reached out to unroll a rubber sheet, draping it over the edges of the table. A final check. Everything was in order. A dark- haired woman in a white lab coat turned on the vacuum pump. There was a faint whoosh as air was sucked out of the rubber sheet through a network of tubing. Then the electricity was turned on full, heating the coils embedded in the aluminum table. Twenty minutes passed. A mild-mannered man, also wearing a lab coat, checked the temperature gauge —150°F. It was time to turn off the heat and start the cooling process. Gary Alden and Marie Fox, director and conservator, respectively, of the Balboa Art Conservation Center (BACC) had successfully preserved another work of art — in this case, Adolph Gottlieb’s Composition 1947, an oil painting from the Santa Barbara Museum of Art. Alden and Fox, with the help of modem technology, had relined Gottlieb’s work.

The Enthroned Christ: Some Russian Orthodox believers used a fingernail to carefully scrape off a flake of paint from the hand, took it home, and brewed it into a cup of tea.

David Covey

Relining has been a method in use since the Eighteenth Century to prolong the lives of paintings whose canvases have so weakened that they are no longer able to hold themselves together. In the Eighteenth Century, a lining was put on like an iron-on fabric patch. An adhesive substance was applied between the canvas and the lining fabric and a hot iron was pressed against the fabric, melting the adhesive and fusing everything together. However, the weight of the iron tended to damage the impasto, the raised brush work of the paint. Today the vacuum hot table eliminates that risk. The rubber sheet is pulled over the painting as tautly as a fitted bedsheet on a mattress, but it conforms to the hills and valleys of the brushwork instead of flattening the contours, and safely presses the painting to its lining.

David Covey

The Gottlieb painting was being relined so that it would be strong enough to travel to a show in Reno. Its problem was that the paint as it dried had formed a series of cupped flakes, like dried mud on a dirt road, and had pulled the canvas up with it. The lining would secure the paint uniformly to the canvas once again.

Every work of art, not just the Gottlieb, begins to deteriorate as soon as it is completed. All our museums have works of art in varying stages of decay. It is the task of the art conservator to prevent and arrest this decay. Many of the techniques used by the conservators at BACC to counteract the aging process seem to verge on magic or alchemy, but there are no secrets which they are not willing to share, and an impartial observer can testify that they do it not with mirrors but with X-rays and chemical solvents and painstaking care. They do their work in two small laboratories in the San Diego Museum of Art in Balboa Park. The rooms have high ceilings and tall, old-fashioned windows. There is a feeling of spaciousness above the crowded work areas where seven staff members come and go, tending to various projects. Works of art in all stages of examination and treatment fill the rooms, paintings and ivories and ceramics and polychromed wooden sculpture. Many of them are hundreds of years old. Some show signs of previous art restoration which may also be centuries old.

The tradition of art restoration is an ancient one. It was once an integral part of almost every artist’s training. Michelangelo had to learn the techniques of art restoration when he was apprenticed at the age of fourteen. In San Diego the tradition is being continued by BACC, where the twentieth-century counterpan of Michelangelo the art restorer is the professional art conservator, who has studied chemistry as well as art history and who can use a microscope as well as a paintbrush.

The change in nomenclature from restoration to conservation reflects a significant change in underlying philosophy. The goal is no longer to restore an object to its original appearance, nor to remodel it according to contemporary standards. Gone are the days of slimming down voluptous Venuses that looked too plump to later eyes, and painting fig leaves or clothing over nude bodies. The goal today is to save and protect all of the original work still extant, and to replace as much of the original aesthetic value as possible by filling in the gaps that have developed.

In the case of a missing Russian right hand, another consideration took precedence over the customary aesthetic ones. The hand belonged to The Enthroned Christ, a fifteenth-century icon from Novgorod. It is a wood-panel painting that usually hangs in Balboa Park’s Timken Gallery but was temporarily on an easel in the BACC laboratory. Sarah Fisher, BACC’s chief conservator, was standing in front of the icon with a paintbrush in her hand. She explained the missing hand: ‘‘The Russian Orthodox worshippers of the icon placed great faith in the powers of the effigy, especially as embodied in the upraised blessing hand. Some of them used a fingernail to carefully scrape off a flake of paint from the hand, took it home, and brewed it into a cup of tea. believing that ingesting it would be beneficial. Over the years the paint was entirely removed from the hand, exposing the wood panel underneath, and today the missing hand has a religious and cultural significance of its own.” Fisher said that although she could paint in a stylistically plausible facsimile, it would be impossible to reproduce the original exactly. Since the exposed wood is aesthetically compatible with the work, BACC’s proposal for treatment suggested leaving the hand missing. The gallery concurred.

A previous restoration of the icon had used the technique of overpainting, painting over a damaged area into an undamaged area. Overpainting may seem desirable because the object once again appears intact, but by covering up some of the original painting it diminishes the historical authenticity and value. The preferred technique today is inpainting, painting in what is missing within an area of damage. Purists advocate the use of rigatino — that is, inpainting with fine lines that from a distance blend in with the original paint but from close up are clearly the work of the conservator.

Treatment for the icon will remove the earlier overpainting and inpaint those areas around the hand and in the background where paint has worn away, and leave the hand missing. Fortunately for the icon, the climate in San Diego is nearly ideal for preserving art. and the wood panel is in good condition. Fluctuations in heat and humidity, the most common disasters that befall works of art, are particularly stressful for paintings on wood panels because the wood shrinks and swells with the changes.

The Russian icon is 500 years old and there are other older paintings in San Diego. The oldest house in San Diego, a Spanish adobe house in Old Town built in 1827, seems almost young by comparison. Comparing paintings and houses may sound like apples and oranges, but a painting is actually very similar to a house. It has an underlying structure, usually a wooden frame. Stretched over the frame is a skin, usually a linen canvas. The skin is covered with a preparatory ground that is analogous to the primer coat of paint on a house. On top of the ground is what we think of as the painting: a layer or series of layers of paint corresponding to the exterior latex on our houses. Finally, a painting receives a coat of varnish which gives depth and luminosity to the colors and renders the coated materials somewhat more impervious to the elements than our unvarnished houses.

We expect to have to repaint our houses, inside and out, every five to ten years, yet we readily assume that a painting will last forever. In fact, each part of a painting is subject to all the deterioration that each part of a house is: warping, cracking, dry rot, termites, blistering, wear and tear and dirt.

One of the earliest paintings of San Diego is a nineteenth-century landscape of Mission Valley from the San Diego Historical Society’s Serra Museum. Marie Fox had left the hot table and was examining a hole in the Mission Valley sky under a microscope. She was preparing to remove a microscopic sample of the sky around the hole, analyze it chemically, and match it with one of the 500 pigments in the BACC collection. The collection, one of only a few such in the world, includes virtually every known pigment ever used by man and comes from a parent collection at Harvard University’s Fogg Art Museum. Fox will fill the hole with wax and cover it with a stable paint that will not change color. “The original paint has changed color over the years.’’ she said, “but the paint we use will blend in now and one hundred years from now.”

For the last fifty years synthetic varnishes have been available which are also stable and resist yellowing. Before that all varnishes were made from natural resins which darkened and became brittle, causing cracking and crazing in the paint layer. If the changes were minor, what resulted was an almost imperceptible and impalpable muting of the original appearance, which is called patina. The patina is considered to enhance the beauty of a painting, in the same way that lines and the softening effects of time can make a human face more alive and interesting.

In other cases, the beauty and longevity of a painting was diminished by cracks and by distortion of the very colors the varnish was intended to enhance, turning blue skies green, crisp white lace a faded yellow. The art conservator’s solution is to clean the painting, removing the old varnish. Gary Alden reached up to a shelf and pulled out an example. It was a seventeenth-century Dutch Portrait of a Woman, sent to BACC from the University Galleries at USC. It had arrived with a murky yellow coat of varnish and with 300 years’ accumulation of dirt and grime hardened onto the surface, darkening it further. Preliminary tests had been made under a microscope to determine what kind of varnish it was and what chemical solvents would dissolve it without removing the paint, too. Tests had been made for each color, for some colors are more sensitive than others and consequently more susceptible to accidental removal. Blacks and reds, for example, need to be cleaned with a milder solvent than whites. After all the tests, cleaning had proceeded cautiously, with cotton swabs. The surface texture of a painting may vary from one spot to another, and such variation affects sensitivity to softening and solubility.

There is a fine line between cleaning and undercleaning. and also a fine line between cleaning and overcleaning. The conservator aims for the narrow space between the lines. The Dutch portrait had been exactly half cleaned when I saw it and the transformation was remarkable. The uncleaned part of the figure had a face the color of old ivory and wore the musty yellow lace and honey black dress that we have learned to associate with seventeenth-century Flemish portraits. The cleaned part of the figure had a translucent white face, sparkling white lace collar and cuff, and ebony black dress. The cleaning uncovered a purity and fragility in the face that had been obliterated by the opacified varnish. Cleaning also revealed the brilliance of detail in the lace that makes the collar and cuff convincingly three dimensional. Alden pointed out another improvement. “See how the lace looks next to the dress on the left, and see how different they look next to each other on the right. The darkening varnish affected the different colors differently, so it was not just the individual tonalities that changed, it was also the contrast and balance between the colors. Cleaning is restoring the balance that the artist intended.” Once cleaning is completed, the painting will receive a coat of synthetic varnish that will preserve the balance.

Some paintings cannot be cleaned with chemical solvents. If the varnish is too tough or the paint too sensitive, or if varnish has been mixed in with the paint so that it is impossible to dissolve one without also dissolving the other, one must use a scalpel and manually remove the varnish bit by bit. “This takes a lot of time,” Alden acknowledged with a barely perceptible shudder.

Next to the vacuum hot table, conservator Alfredo Antognini was hunched over an eighteenth-century Portrait of Mrs. Birch by George Romney. It was sent here from the Phoenix Art Museum after a hole was poked through the eye of its subject. Rather than patch the hole, leaving signs of repair, a previous lining was being removed and a new lining would be put on. Antognini waved a paintbrush in one hand and a scalpel in the other as he described what he was doing. “The solvent I am using is water, diluted — so to speak — in a flour paste, to soften the glue gradually. Then the old lining can be peeled away. ” He was applying the paste in a checkerboard fashion, skipping every other square at first, to prevent warping from a sudden uneven change in moisture. The painting would then be ready for the vacuum hot table and finally for inpainting.

Occasionally a procedure more drastic than relining is necessary. When the preparatory ground or wood panel itself has become unstable, a "transfer of color" may be performed. This means removing the paint from its original surface and transferring it to a new surface. How? “Very carefully,” said Alden. “First, a thin facing of tissue or fabric is applied to the front of the painting, using a removable adhesive. Once the paint is securely affixed to the facing, the backing is removed by scalpel and a new backing applied. Finally, the adhesive is dissolved and the facing removed.” While most important paintings of past centuries have been relined. transfers of color have always been a procedure of last resort. “There has only been one transfer done in this lab,” said Alden, “and we may be doing another one later this year.” They are done less frequently than in the past, now that the risks are better understood.

The wish to save dying works of art has been fairly constant, although in the Nineteenth Century John Ruskin said a work of art has a right to its own life and spoke of the beauty of decay. In recent years there have been artists who have created works of art that are not intended to be permanent, and their impermanence is itself a statement about art. The consensus of opinion, however, has been that works of art should be preserved and protected as repositories of our cultural heritage, as objects that tell us something about our values and our dreams. It was therefore shocking when a 1969 report from the American Association of Museums questioned “whether even a percentage of the museums in this country are doing anything more than presiding over the steady deterioration of that which they have been instituted to preserve” and called for federal funds to establish regional conservation centers.

BACC is one of six regional art conservation centers in the country today. The plan to have a center in San Diego was first formulated in 1973 by Henry Gardiner, director of the San Diego Museum of Art, and George Stout, conservator and ex-director of the Isabella Stewart Gardner Museum in Boston (a uniquely appropriate position for an art conservator: Mrs. Gardner bequeathed her Venetian palazzo to the city of Boston with the stipulation that everything in it — all the paintings, sculptures, furniture and lighting fixtures — be preserved for one hundred years exactly as she had left it). In 1974 Richard Buck, who in 1952 had founded the world’s first regional conservation center in Oberlin, Ohio, came to San Diego and established BACC.

As a regional center BACC serves a number of institutions that individually would be unable to maintain such a facility. BACC has ten member-museums: San Diego Museum of Art (formerly Fine Arts Gallery of San Diego) and Timken Gallery in Balboa Park, La Jolla Museum of Contemporary Art, Bowers Museum in Santa Ana. Laguna Beach Museum of Art, University Galleries of the University of Southern California, Santa Barbara Museum of Art, Hearst State Monument in San Simeon, Phoenix Art Museum, and University of Arizona Art Museum in Tucson.

BACC inspects its members’ collections and makes recommendations for maintenance (how to hang whom where and why) and short- and long-range conservation priorities (it’s not necessarily women and children first), and examines and treats individual objects sent here. BACC also offers a public clinic every Tuesday morning. The clinic gives individual art owners advice but does not appraise or authenticate, nor does the center undertake treatment. A recent Tuesday morning had brought a wooden angel weakened by insect tunneling, a fragmented jade sculpture, and a portrait of the owner’s grandmother that was mildewed and improperly framed. Gary Alden diagnosed the problems, estimated the cost of treatment, and made referrals to private conservators. Not all of the owners were sure they could afford the price of conservation in the immediate future.

There are about fifty works of art in the BACC laboratories at the moment: Last year, 113 objects came to BACC and another forty were carried over from 1977. Each object has its unique problems and requires individualized treatment. There are two fundamental principles underlying all treatment: stability and reversibility. All conservation materials should resist change themselves and not precipitate change in the original materials. And any conservation process or material that is added to the object should lie undo-able or removable. To repair ceramics, for example, gaps are filled in and joints made with a substance, weaker than the original ceramic, so that any future stress that induces breakage will do so at the point of repair and not at a previously undamaged part.

BACC has its own scientific equipment, and access to the resources of large conservation centers. Scientific knowledge and technology enable the conservators to avoid the hit-or-miss effect of old restoration methods, which sometimes helped a work of art and sometimes damaged it further. The process by which scientific developments are adopted by art conservators is itself unpredictable. X rays, discovered in 1895, were almost immediately used to look at paintings, but it was decades before they were seriously used in art conservation. The laser may be a current example whose time has not yet come.

A laser produces an intense beam of light of a very pure single color, intense enough to vaporize the hardest and most heat-resistant materials. Since the first laser was constructed in 1960, lasers have been used on assembly lines, in eye surgery, and to measure the distance from here to the moon. A San Diego physicist, John Asmus, has pioneered the exploration of the laser’s usefulness in art conservation. Asmus began his art conservation work in Venice, Italy in 1972. He went there to make holograms of some marble statues. (A hologram is a special kind of photograph which, when illuminated by a laser beam, produces a simulated three-dimensional representation of the object that gives a more lifelike image than an ordinary photograph can.) The Venetian conservators told Asmus that their most time-consuming task was cleaning the statues and asked him if the heat generated by the laser would remove surface dirt. He experimented and — Eureka! — it worked. In fact, the laser works particularly well on white marble and other light-colored stone discolored by dark encrustations of dirt and grease. The heat from the laser vaporizes the dark material; when it works through to the marble, the whiteness of the marble reflects the laser light back and one knows it is time to turn the laser off.

Although there are many different kinds and sizes of laser, thus far Asmus has used only a ruby laser, which is relatively inexpensive. Its portability allowed him to take it to the second-floor balcony of the Doge’s Palace in St. Mark’s Square in Venice to clean several columns. The main disadvantages of the ruby laser are its limited power and capacity. Asmus was once sent, by airmail, a one hundred-pound tombstone from England. It was so black with dirt that the epitaph was illegible. “It was responding spectacularly to cleaning,” he recalled, “but it took more than an hour to clean a square inch. And then the laser became overloaded and blew up.”

Lasers are exceptionally good for fragile stone that would crumble at the touch of other methods. They can also clean paintings, though the variability in surface texture makes the process more complicated and tedious. The laser may work wonders, but it has hardly become the aspirin of the art conservation world. It is expensive, requires technical proficiency, and it is consequently very little used. However, Asmus foresees the day, perhaps by the year 2000, when the laser will be cheaper than the manual labor for some things.

Flash lamps are another scientific device used by John Asmus for cleaning art. They are like giant photo flash cubes, less precise than lasers but able to clean large areas more quickly, and a less damaging alternative to sandblasting for cleaning buildings. Asmus used flash lamps to uncover the original murals on the dome and rotunda of the state capitol in Sacramento. There were nine layers of overpainting. Unfortunately, the flash lamps revealed that the murals, once considered vulgar, had been wire-brushed away.

Another scientific technique, ultrasonics, helped Asmus find a lost Leonardo da Vinci. It was a mural of the Battle of Anguiari in the Hall of 500 in the Palazzo Vecchio in Florence, Italy. Prince Machiavelli had commissioned Leonardo to paint it. About forty years later the Medicis returned to power in Florence and with the change in political regime the political propaganda of the battle scene became unacceptable. It was overpainted. New walls were erected in front of the old and the roof was raised. It seemed reasonable to hope that under the new walls could be found the perfectly preserved work of Leonardo. However, the Hall of 500 is the size of a football field and no one knew where to look. And the frescoes on the new walls were also hundreds of years old. and also precious. The answer was not to indiscriminately start tearing down walls. Hence, the ultrasonics.

Asmus sent sound waves into the walls. The time they took to pass through the walls, the scattering of the waves which indicated a change in the wall material, and the tones of the echoes that came back enabled him to calculate where the old walls were and what was on them. It was a long process. One day when he was on the top of the scaffolding in one comer of the hall, he came upon an inscription on a battle flag. It read, cerca trova — he who seeks shall find. “I took it personally,” said Asmus, “and kept on looking.” At last he did find signs of the Leonardo. A small hole was drilled and traces uncovered; but Leonardo’s battle scene had been scraped away, a victim of political censorship.

It may be a long time before BACC has access to ultrasonic devices, or even a laser of its own. A more immediate hope is to have the money and space needed to treat paper damaged by light and moisture. Next to paintings, paper — which includes prints, drawings and books — is the medium of highest demand for art conservation. Historically, the greatest art disaster and most massive conservation effort involved paper. When the Arno River in Florence, Italy, flooded in 1966, thousands of prints, drawings, and books were waterlogged and mud-spattered. Other works of art were destroyed or damaged as well, but the sheer volume and effort needed to save the paper were the most staggering facts in the aftermath of the flood. Hundreds of volunteers came, many of them American students, who washed off the mud, flattened every page and paper, and controlled drying to prevent curling. The flood in Florence quickened interest in conservation in the U.S. and around the world. Since then, significant progress has been made in the new tradition of art conservation, with its union of art and science. In San Diego, conservators and scientists are adding to this new tradition, to the benefit of artists past and present and we, the public.