Painting Conservation, Step by Step

Some people call conservators the "magicians" of the art world

Oftentimes, the colors of older paintings have a brown and yellow tint caused by an organic varnish that has yellowed with the passage of time. Such tints can become so opaque that no true color or depth of background is visible, making the actual painting seem to have almost disappeared. When this happens to a painting, a restoration, conducted by a trained conservator, should be considered.

Many people think conservators are the “"magicians" of the art world. They are actually trained art historians, chemists and materials scientists, and they combine these areas of knowledge with the manual dexterity and color sense of a skilled artist. A good painting restorer or conservator must be as talented as the original artist if his or her handiwork isn't to leap out at the viewer as a clumsy repainting of the original art.

To follow is a description of the painting restoration process that highlights the details a conservator must examine and the types of information he or she should be knowledgeable of when restoring a work of art.


The Restoration Process

Upon receiving a work that needs restoring, a conservator should examine the work, making note of the signature to identify the artist. Trained as an art historian, a conservator should be aware of the style of that period, the painting technique, and the materials available to an artist of that time. This knowledge will help the conservator identify the pigments and fabrics that were popular and available to the artist and help him or her determine the best approach for the restoration.

Conservators will often remove the frame and look under the “tacking” edge (a thin area hidden beneath the edge of the frame) to uncover pigments that are light and clear. This helps a conservator see the true color scheme.

A conservator will often continue examining a painting with the aid of an ultraviolet light, noting a greenish or blueish fluorescence on the surface of the painting. Trained in chemistry, the professional conservator knows that resinous, organic varnish, like Damar or Shellac, creates such colored luminosity when subjected to incident light or other electromagnetic radiations of shorter wavelength, especially violet and ultraviolet light.

If a layer of varnish is discovered, a conservator will perform a small cleaning test to remove it. Using a solvent on a cotton swab, a conservator gently rubs open a window, displaying the true color beneath. This will help the color palette used by the artist become apparent. The whites are white, the blues are blue. And so it continues as each pigment reacts to the solvents—— different solvents in different strengths with different rates of evaporation.

A conservator continues this complicated process, examining with a magnifying glass and a microscope, using different lights, making notes and taking photographs at each stage to carefully document every part of the restoration.

An oil painting is composed of multiple layers of pigments suspended in medium (oil and turpentine). Regardless of its subject, a painting is simply a created illusion, striving to depict three-dimensional reality on a two-dimensional surface. All of pictorial art history is simply a studied investigation of ways to create depth, air and space. And, as with any illusion, these methods are extraordinarily fragile and subtle. It is with these that the artist claims virtuoso skill.

Wearing a jeweler’s head-mounted visor, a conservator carefully removes each layer of varnish and then washes the area with a "retarding" solvent to remove any residual solvent and reveal the underlying image. No pigment is removed or abraded. This delicate work progresses slowly and incrementally, stroke by stroke, each viewed under a magnifying lens. As the old layers of varnish and dirt are removed, the painting slowly begins to appear.

This is not magic but a meticulous chemical process performed by a trained and steady hand accompanied by a highly educated and experienced eye. A conservator's training and care insure that the solvent does not go too far, either removing the original pigment or chemically burning the surface. There is no margin for error since any loss of pigment is irrevocable.

Slowly, the work continues until all the varnish is removed. The three-dimensional illusion not only remains intact but comes alive.

A conservator, trained in material science, also can address a painting’s structural problems. Conservators will often remove the painting from its stretcher and cover the front with a protective “facing” composed of wet paper and emulsion. This protects the surface while he or she uses a surgeon’s scalpel to carefully remove years of dirt and grime from the back of the canvas.

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Any material used to repair or strengthen the canvas must be both chemically compatible and reversible: that is, any material used on a work of art must be able to be removed without harming or discoloring the original paint.

Finally, a conservator will remove residual adhesive and restretch the painting onto a new museum-quality stretcher. Once this is complete, the conservator is ready to repaint.

The conservator, with the hand of a trained artist, brushes a synthetic, nonyellowing, removable varnish over the face of the painting. This is called an “isolating varnish,” because it separates the original painting from any paint that will be added to reconstruct the design. Dry pigments are used in synthetic, nonyellowing medium, and paint is used in areas of color loss, using exactly the same colors, texture and surface sheen of the surrounding areas. The principle here is that the conservator’s paint should only touch areas of actual paint loss and should never overlap undamaged original paint.

This demanding work is done under the jeweler’s visor using a pointillist technique and tiny sable 00 or 000 brushes. Once this "in painting" is finished, a conservator will brush on one final coat of protective varnish.

When these steps are complete, the painting has been restored. It is no longer fragile. The colors are vivid and alive, revealing the artist’s original vision. All materials used in the restoration are noninvasive and can easily be removed without endangering paint layers or affecting the work in any way. The painting can be enjoyed for years to come.

Art Care Tips
As an advocate for preservation, a conservator should inform clients of techniques for preventing damage to their art. Here are a few basic guidelines:

  1. Paintings should be framed with new and secure hardware and hanging materials.
  2. A nonacidic backing board should be attached to the reverse of the stretcher to protect the painting against puncture.
  3. A painting should be hung on an appropriate wall in a stable environment—never over a fireplace or air duct, and not on an exterior wall or in direct sunlight.
  4. A painting should be examined periodically by a professional to ensure its continued beauty and its preservation against the ravages of time.


Selecting a Conservator for Your Restoration Project

Conservation has been called "the humble art." The conservator, preserver of the past, is ethically bound to do nothing to destroy the intent of the original artist. He or she is an advocate for the preservation of a cultural property.

When selecting a conservator, it is important to review the individual's credentials, make sure that he or she prescribes to the same philosophy mentioned above, and check his or her previous clientele to ensure that he or she has worked with similar art and that his or her customers were satisfied.

A database of conservators who are affiliated with the American Institute of Conservation (AIC) and other similar professional associations is available on www.art-care.com