Romare Bearden, Mother and Child, 1968. Mixed media.

In this mixed-media work, Romare Bearden used a variety of papers, from construction paper to photographs and then glued them to a Masonite support. Most modern glues and papers are vulnerable to discoloring, since the acids used in their manufacture cause them to oxidize over time and turn brown. Photographs are vulnerable to additional problems, such as the eventual migration of silver to the surface to create a distracting sheen.

This collage retains an early box frame fronted with plexiglass, which had protected the surface but some cleaning was still necessary. This proved especially difficult compared with a painting because liquid solutions can react unpredictably with different pigments. Conservation experts were able to promote the stability of the paper with a buffering solution applied delicately to problem areas, counteracting the activity of acids to some degree. Though some slight distractions remain, cleaning and consolidation have brought the collage together remarkably well.