40th Annual Meeting, Objects Session, May 11th, “The Treatment of a Mi’kmaq Box Made of Birchbark, Porcupine Quills, and Iron-Dyed Spruceroot”, Carole Dignard

The multi-step treatment of a Mi’kmaq birchbark box was outlined in this talk presented by Season Tse. The circular box with four stacks of rings is made of birchbark and decorated with dyed spruceroot and porcupine quills. Before treatment, it was exhibiting significant instability due to a deformation of the lid, the separation of the rim from the lid, and localized deterioration of the dark brown dyed spruceroot. There were also reported losses in the birchbark, unknown instability of dye components to light, losses to the spruceroot, and overall surface dirt.

The treatment began with a cleaning of the quillwork with saliva. This step revealed the brilliance of the blue-dyed quillwork and the presence of yellow-dyed quillwork previously unnoticed. The sensitivity of the dyes to light damage was tested using microfade tests with a Blue Wool dye scale ranging from 1-8. The dyes were found to between 3-4, which indicates that the dyes would survive 100 years at 50 lux for 8 hours a day before noticeable fading occurred.

The lid of the box was deformed and warping. After testing using deformed samples of birchbark, they found the appropriate solvent and pressure parameters to treat the deformity. A methanol vapor chamber was used under 6 psi vacuum conditions for three days to reform the lid. The treatment was mostly successful though some springing occurred.  Broken spruceroot was stabilized, paper pulps fills were used for the loss of birchbark, and the lid was attached to the rim with Japanese tissue paper hinges.

The investigation and treatment of the dark brown colored spruceroot could be considered the highlight of the talk. Through their investigation into the colorants of the material they found that the colorant had both iron (II) ions and tannins present. This combination has been reported time and again as the source for severe deterioration of dyed cellulosic material. The concentration of iron (II) ions were identified and monitored throughout the treatment with iron indicator paper. To stabilize this deterioration they choose calcium-phytate solution, developed by CCI, to complex with the iron thus arrest the oxidation of the spruceroot material.  Because the box could not be immersed in to the solution the application was with brush. After each application the ion content was monitored. They found that five applications were enough to stabilize. However, the application of the solution was not without complications and risks. The spruceroot swelled during the application and staining of neighboring spruce root occurred due to migration of the iron ions.