The Repair & Restoration of Antique Paintings
There is no “one size fits all” approach to painting restoration, as each work has to be carefully examined to determine which process and techniques will be best suited for the piece. Trained art historians, chemists, and materials scientists combine extensive areas of knowledge to assess original areas of a work and determine the least invasive solution for repairing loss.
First, the painting undergoes initial assessment. Conservation associates should be well educated on the style and period of the work they’re evaluating, as this knowledge will help determine painting techniques, materials available to artists during the time, and pigments and fabrics that were commonly used. X-rays also reveal how the work was composed, which allows the conservator to formulate an outline of the painting or work based on differing absorption of paint.
Assessing Loss of Paint
Next, infrared imaging is used to view the original drawings and losses of paint underneath the surface of a painting. Recently, technological advancements in art restoration have included cameras with fixed wavelengths. Because different pigments and materials reflect or absorb various wavelengths differently, these devices can help distinguish them. They allow conservators to pinpoint carbon-based drawings, for example, using distinctive wavelengths at about 1,700 nanometers. This is part of a larger movement aimed to eliminate previously destructive techniques and help identify varnish layers.
Removing Discolored Varnish
Once an accurate picture of the original painting is in place, the next step is to find the appropriate solvent mixture to remove discolored varnish layers, if applicable. The development of spectroscopy—a technique used to observe vibrational, rotational, and other low-frequency modes in a system—has since made it easier to determine the exact composition and characterization of varnishes.
Repairing the Painting
After the identity of the varnish is determined and outer layers are removed, it can be repaired. An example of one way this may be done in modern practice is as follows: An intermediate coat of varnish is applied to the original painting to physically separate the new paint from the old, and ensure that any future restorations can be done without affecting the work’s original layers. This allows for stylistic fluctuations, which are common in art conservation. The conservator will carefully inpaint damaged areas using dry pigment mixed with synthetic non-yellowing solvents to ensure that a professionally restored work will rarely need further conservation.