Sebastiano Mainardi: The Science of Art

00:00:00 Sebastiano Mainardi's altarpiece was painted exactly five hundred years ago. Although it survives more or less intact,

00:00:09 its appearance has changed drastically since 1507, the year in which the artist signed and dated it. Its fragile condition resulted in its removal from public view in 1965.

00:00:23 The extent and complexity of the conservation treatment it required meant that it would remain in storage for more than forty years.

00:00:34 Before beginning any conservation treatment, the conservator must thoroughly examine and document the painting with many different photographic and scientific techniques.

00:00:44 The painting was x-rayed to determine the extent of damage to the original paint and wood-panel support, and to provide information

00:00:53 on the artist's materials and techniques. A new state-of-the-art computed radiography system allows the conservator to scan

00:01:02 the exposed x-ray plate and view it on a high-definition screen. The digital x-ray image can be manipulated

00:01:10 to bring out details, such as the fabric patch found below the paint that covers a knot in the wood panel.

00:01:20 The painting is photographed in several types of lighting to reveal details of its condition. A raking light from a side angle dramatically shows how the paint is cracking,

00:01:31 blistering, and flaking away. Conservators use ultraviolet light to help distinguish the original artist's paint from any paint added later

00:01:42 by other artists or restorers. The dark purple areas were not painted by Mainardi, but are 20th century restorations to cover up damages.

00:01:54 Italian Renaissance painters often drew their compositions on their panels before applying the paint. Infrared reflectography, using

00:02:04 a special video camera that records infrared radiation invisible to the human eye, allows the conservator to see through the paint

00:02:13 and make visible Mainardi's drawing that hasn't been seen in 500 years. Stereo microscopes are used

00:02:23 to greatly magnify the surface of the painting allowing the conservator to closely examine the artist's materials and painting technique, as well as

00:02:33 to identify areas of damage. Treatment of the entire paint surface includes infusion of a warm adhesive into every crack

00:02:43 and area of loss and damage, a small section at a time. Then, laying Japanese tissue over the wet adhesive to hold the brittle paint in place

00:02:54 and soak up any excess adhesive. Heat and mild pressure from a miniature tacking iron reattaches and stabilizes the now flexible paint layers.

00:03:05 Once the paint is set back into place and the tissue is completely dry, the tissue and residual adhesive is very carefully removed.

00:03:17 After lengthy planning and testing, the conservator uses a carefully designed mixture of solvents to safely remove the old varnish

00:03:27 without any harm to the original paint. The picture has been repainted by restorers many times over the centuries to cover up damages and losses.

00:03:38 Removal of these repaints with a variety of solvents has revealed the beauty of Mainardi's surviving original paint.

00:03:46 Over the coming months, conservators will apply clear varnishes and fill and carefully in-paint the damaged and missing original colors

00:03:56 with stable and safely reversible materials returning the painting to a visual state that will permit it to go back on display in the permanent galleries.

00:04:07 After the paint has been completely stabilized, paper facings are carefully attached to provide extra strength in critical areas of the painting

00:04:17 to protect it during structural treatment of the wood panel. The painting is very carefully placed facedown on specially designed and constructed sawhorses,

00:04:27 permitting the back to be examined and photographed. The conservator must first carefully saw through small sections of the heavy mahogany cradle

00:04:38 that is glued to the back of the original poplar wood panel. A chisel is used to carve away chunks of the mahogany to expose

00:04:47 the back of the painting. Once an area is completed, the conservator repeats the same process in small sections until the entire cradle is removed

00:04:59 along with the crossbars. This took several days to accomplish. Old glue and wax adhesives are carefully removed from the back of the panel

00:05:10 by applying a specially designed gel to soften and swell the residues without harming the original wood.

00:05:19 The splits and cracks in the very fragile panel must now be repaired by carving away damaged wood, and replacing it with a similar wood

00:05:29 to strengthen it. The conservator uses very sharp chisels and scalpels to precisely cut V-shaped channels into the wood

00:05:39 almost all of the way down to the painting on the other side, in order to expose the splits and cracks that require repair.

00:05:49 Old Italian poplar is used to make the wedges that will be glued into the newly cut channels. The wedges are cut into the right size and shape with a wood plane.

00:06:02 The repair wedges must be a perfect fit in the channels, so adjustments are made with a chisel and scalpel where they are needed.

00:06:11 The wedges are glued in place. Then, when the glue is dry, the new wood is shaved down with a chisel until it is flushed with the original panel.

00:06:23 Some of the old repairs were made with woods that were not compatible with the original panel and were causing further damage.

00:06:32 A router is used to carefully remove these large areas instead of a chisel. These areas were then properly strengthened by gluing in

00:06:41 pieces of the correct wood. To protect the fragile wood panel, and act as a moisture barrier to reduce the panel's response

00:06:51 to changes of temperature and humidity, a stable acrylic polymer is brushed into the back of the painting.

00:07:01 One hundred wooden pegs with rotating metal rods are glued to the back of the panel. These mechanisms will hold the new support strainer

00:07:11 to the back of the painting. A custom made wooden strainer is fitted to the support mechanisms. The strainer is shaped to follow the curvature of the panel.

00:07:23 Custom made springs are fitted onto the threaded metal rods, then brass nuts are carefully tightened to provide the correct tension

00:07:32 for each of the 100 support mechanisms, to gently but firmly hold the new support strainer to the painting.

00:07:41 The painting is finally structurally sound and can be placed upright again. The new support structure will allow the painting to safely flex

00:07:51 in response to changes in temperature and humidity to prevent future cracking or splitting. IMA conservators can now resume treatment

00:08:01 of the paint surface to prepare the altarpiece for its return to the exhibition galleries for the first time in over forty years.

Sebastiano Mainardi: The Science of Art

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