Dating from the late 1700s, George Romney's drawing The Infant Shakespeare Nursed by Comedy and Tragedy became grossly discolored over the years, as shown in the first of these two photographs.
The circumstances under which the discoloration occurred are unknown. Often such an effect is caused by exposure to light and atmospheric pollution. A rectangle of some material apparently covered one part of the drawing, shielding it from harm.
Folger conservators restored the drawing to its original state through two treatment steps. First, they washed and dried the paper. Then, in a process known as “light bleaching,” they subjected the drawing to a carefully regulated exposure to tungsten lights. The superb result looks far closer to the drawing Romney originally produced.