ConNext-2021

16 Genuine or Imitation Materials for Reconstructing Turtle Shell Mouldings KEYWORDS: conservation; infills; imitation materials; tortoiseshell; turtle shell This research was prompted by the conservation-restoration of an early 18 th century tabernacle with turtle shell veneer and turtle shell mouldings. Literature research was executed to explore possible methods and materials to make infills for turtle shell decoration. Based on this research materials were selected for the treatment of the tabernacle. Figs. 1 and 2. All assessed publications address the ethical issue of using genuine turtle shell. Since the 1970’s the use of turtle shell has been severely restricted because several species of sea turtles are threatened with extinction. The material however is still used by conservators if it is available in old stock. To serve as a substitute for turtle shell, a material must be able to match several characteristics of the genuine material. These are a specific translucency, homogeneity, typical stains with a depth into the material, the potential to be worked into mouldings and to be polished to high gloss. It is an asset if stains can be custom applied to match original material. Several natural and synthetic polymers match these criteria to various extents. In conservation practice large lacunae are usually filled with horn, genuine turtle shell from old stock, acetate film, dyed cast polyester or epoxy resins. Small lacunae are traditionally filled with pigmented wax or various varnishes and resins, more recently also with putties in an aqueous medium. In more and more conservation treatments lacunae are left as they are. No material is able to replicate turtle shell in all its aspects, and the genuine material is still used when available. Convincing results however can be obtained with other materials, such as horn, wax or (synthetic) resins. For the treatment of the tabernacle a combination was used of infills made of genuine turtle shell, pigmented wax, and filled and dyed epoxy resin. info[at] welmoedkreb.nl