pigmented colorants: dependence on media and time - Cornell ...

in situ experiences deposition of dust and erosion from airborne chemicals on the
finished surface, historic work suffered from layers of candlelight soot. Today, at
least the candles have been replaced, though electric lighting still poses a fading
threat to the materials.
The preservation of artwork falls into categories. Conservation is to neutralize
any adverse effects, therefore minimizing any progressive deterioration so that a
work will remain intact for as long as possible. Preventative measures can help
alleviate poor handling of materials and extend their lifespan. Restoration involves
cosmetic treatment under expert care in order to return an object to its original
appearance. Complete restoration is typically more controversial, as while it should
be reversible, it often involves some irreversible change to the original work in order
to achieve results.
Restoration of the artwork on the walls and ceiling of the Sistine Chapel in
the Vatican City, Rome, was completed in 1990. This restoration was initially
surrounded by a heated controversy in the art world, as some claimed it a break-
through revelation, while others felt it ruined the masterpiece. A brown patina
had developed over centuries, composed of candle smoke, soot, and repeated appli-
cations of poor quality varnish (varnish is a transparent coating used to enhance
the optical properties of a work, as well as protect it from outside elements). It
was argued that the patina harmonized the bright colors. Figure 1.1 illustrates the
magnitude of change in restoring this piece of artwork.
While not a trivial task, trained restoration professionals can routinely achieve
miraculous results from work that has suffered presumably irreversible damage.
Typically, extensive damage (such as fire damage, watermarks, tears, and yellow-
ing) can be repaired. Yet, this presents the question for art historians and conser-
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