Cartonnage is the painted material that covers many mummy bundles. Like a plaster cast, it is made of layers of fabric (usually linen) that are wrapped around the bundle and then covered with a smooth, white layer of plaster. After it is dry, the plaster surface can be painted with designs and Egyptian religious symbols.
The Walters Art Museum includes a number of examples of cartonnage, including several small fragments. One of these fragments was recently in the Objects Conservation lab so that conservators could evaluate its condition and make recommendations about how best to preserve it.
This fragment would originally have been part of a larger, three-dimensional cartonnage covering for an animal or human mummy bundle. At some point before it came to the museum, it was cut down to its current size, pressed flat, and glued to a modern backing board. This is not an ideal method of mounting this fragment and is not an approach that would normally be used here in the museum. However, it was decided not to remove the fragment from this mount because the cartonnage is very fragile and the risk of further damaging it during removal is too great.
The fragment shows signs of other damage from water, light, and air. To identify the materials present on this fragment, and how they may have changed over time, a combination of non-destructive examination techniques was used. A binocular microscope was used to examine the surfaces very closely for signs of wear and deterioration.
Most Egyptian paints from this time period consist of pigments bound with gum Arabic, a natural gum made from the sap of Acacia trees. Gum Arabic is still used today as the binder for most watercolors. On this cartonnage fragment, the gum Arabic has deteriorated over the past 2,000 years, meaning that the pigments are no longer very well adhered. The fragment therefore needs to be covered to protect the pigments from abrasion.
The pale yellow areas of the fragment appear very faint to the eye, but under the microscope, they appear quite different. Bright yellow, irregularly shaped pigment particles of various sizes are visible. These are characteristic of orpiment; a golden yellow, naturally occurring mineral pigment. This pigment was used extensively by ancient Egyptians, but we now know that it fades over time when
exposed to sunlight. To preserve the traces of yellow pigment that are left, the fragment will be stored in the dark.
Stay tuned for part 2 of Cartonnage: Fragments of a Mummy
Find out about other mummies and cartonnage at the Walters Art Museum: