Conservation and restoration of woodblock prints

[1] Fibers of Chinese woodblock prints come from five different plant groups: hemp, bark, rattan, bamboo, and grass.

Paper was generally thin, because woodcuts were made in larger batches, and were relatively cheap.

The pigments were composed of both light-stable inorganic materials such as metals and earth compounds as well as organic colorants such as indigo.

[4] Heat can accelerate the rate of mechanical stresses in organic materials and cause the structure to become brittle or unstable.

[4] Pollutants found in the air can interact with materials on woodblock prints and cause them to deteriorate at a quicker rate.

For example, when exposed to sulfur-containing gases, red lead pigments will turn a metallic brown/black color.

A common cause of holes in Japanese woodblock prints is the deathwatch beetle (Xestobium rufovillosum).

[4] The paper of woodblocks are often made of wood fibers and may react to non-archival quality storage materials.

Ultraviolet-filtered, Plexiglas-glazed frames do little to protect woodblock prints from light damage over time.

The Martyrdom of Two Saints from the Los Angeles County Museum of Art is an Italian chiaroscuro woodcut by Antonio da Trento that had cuts in the support.

When conservators looked more closely at this artwork in 2016, they also saw unusual discolorations that proved that newer materials were used to conserve the piece in the past, and the added colorants faded at a much slower rate than the original colorants, leaving much darker stains.

It is housed at the Library of Congress, and underwent conservation in 2012 for the exhibit, Sakura: Cherry Blossoms as Living Symbols of Friendship.