History and current applications of freeze drying method used in waterlogged wood conservation

Waterlogged wooden artefacts should not be allowed to dry without any conservation work. One of the most widely used methods in the conservation of these artifacts is the freeze drying method. Freeze drying, which is used in many areas especially in the food and pharmaceutical industry, is a drying method used to remove water or solvent from the object through sublimation. Different conservation methods have been developed as a solution to the problems encountered during and after drying of waterlogged wood. In different conservation laboratories around the world, conservation specialists who try to bring stability to waterlogged wood prefer the freeze-drying method, which is relatively more expensive and complex in comparison to the other methods. In this thesis study, the development of the freeze-drying method and the different applications of the procedure are investigated with a literature review. In order to better understand the method, the structure of wood, detection methods of deterioration of waterlogged wood as well as other conservation methods are explained. The principles of the freeze drying method in the conservation of waterlogged wood are described, the development of the method is narrated by giving examples from applications in different countries, and the current applications of the method are explained again with examples. In conclusion, it is shown that the freeze-drying method can be used safely in the conservation of waterlogged wooden artifacts and futher studies should be carried out on new applicable methods.