Crucifix, detail showing dust

Environmental effects

Many external factors contribute to the deterioration of works of art over time. Fluctuations in relative humidity and temperature can cause cracks and flaking in paint and plaster. Dust, soot, and other pollutants accumulate on surfaces, obscuring color and form. Exposure to excessive amounts of light accelerates the deterioration of materials by fading some colors or darkening varnishes.
Crucifix, detail showing substantial amounts of accumulated dust (1999 photo)
The Triumph of Religion