Determining the Presence of Spalted Wood in Spanish Marquetry Woodworks of the 1500s through the 1800s

Seri Robinson

doi:10.3390/coatings7110188

Abstract

The process of using fungal-colored wood (spalted wood) for marquetry and intarsia woodworks in Italy and Germany was very popular from the 1400–1600s, with some instances continuing as late as the 1800s. While spalted marquetry in these countries is relatively well documented, less is known about its use in other parts of Europe. One of the primary reasons for this lack of knowledge is the difficulty in identifying spalted wood, especially the blue-green variety produced from Chlorociboria species, from wood dyed with copper-based compounds or other synthetics. The most reliable testing method involves destructive sampling, where a small piece is taken from the work, the pigment extracted, and an analysis performed. Such sampling is simply not feasible, nor often allowed, on ancient artwork. To make a reliable, non-destructive identification of spalted wood, a visual method based on anatomical characteristics of spalted wood was developed to differentiate spalted wood from dyed wood. High-resolution pictures were taken from wooden artifacts containing blue-green colored wood in collections at the National Museum of Decorative Arts (MNAD), the Royal Site Monastery El Escorial and the Bilbao Museum of Fine Arts in Spain. The concentration of pigment in the rays, the color distribution, the size of the piece and the date of production, were analyzed. With the use of this new visual method, it was possible to determine that intarsia artifacts, held in Spain but of Augsburg origin from the 1500–1600s, contained spalted wood details. Meanwhile, Spanish and Italian intarsia artifacts from the 1800s were found to only contain dyed wood.

Highlights

Intarsia and marquetry are ancient wood art forms that evolved from inlay techniques using ceramics and metals
As most museums and collectors have a great deal of stored wood artwork with unknown composition, but are unwilling to have small pieces removed for destructive HPLC analysis, a more reliable, nondestructive test is needed to determine xylindein presence in ancient marquetries
A spalted wood identification checklist was developed as a fast, non-destructive method to identify the presence of blue-green colored wood by Chlorociboria sp., and thereby differentiate the spalted wood from dyed wood, in marquetry artifacts between the 12th and the 20th century

Summary

Introduction

Intarsia and marquetry are ancient wood art forms that evolved from inlay techniques using ceramics and metals. They involved very small pieces of wood (veneer, for marquetry, and larger pieces for intarsia), often colored, and were glued together onto a framework to make a larger image. Of particular interest in these works was the use of non-wood items, such as tortoiseshell and mother of pearl, and naturally colored pieces of wood (wood that was not dyed, but rather, found in a colored state) This wood, known worldwide as “spalted” wood, was a highly sought after commodity item for woodworking guilds.

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