Lecture 36 - Susan Braovac & Fabrizio Andriulo

Susan Braovac & Fabrizio Andriulo, University of Oslo

Overview

Conservation of waterlogged archaeological wood using alum salts (potassium aluminum sulfate, ammonium aluminum sulfate) was a method used in the past to treat highly degraded wood. It was used on the Viking Age wooden finds from Oseberg, recovered in 1904 near Tønsberg, Norway. Today this wood is very acidic (pH ≤ 2), mainly due to the acid absorbed during the alum treatment. High acidity has caused the wood polymers to undergo a slow degradation over time. In order to slow down degradation, the research project Saving Oseberg investigates retreatment methods for these finds. In some cases retreatment cannot undergo water-based methods. For such objects, we are currently testing alkaline nanoparticles (calcium hydroxide in isopropanol) to deacidify the wood. We present a background of the alum method, facts about calcium hydroxide nanoparticles and show ongoing practical work using these.

About the speaker

Dr. Susan Braovac is an archaeological conservator in the research project Saving Oseberg (SO) at the Museum of Cultural History (2014-20). She has investigated the problems of alum-treated wood since the late 1990s. Dr. Fabrizio Andriulo is a conservation scientist who is a post-doctoral fellow in Saving Oseberg, and specializes in application of alkaline nanoparticles to acidic wood. Pia Kristina Edqvist is an archaeological conservator and joined the SO team in April 2020.