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A set of 19th-century furniture in black lacquer, on papier-mâché or on turned wood, has been subjected to an in-depth observational, historical and chemical study. The results show four different technological approaches: two for the papier-mâché objects and two for the wooden chairs. The cyclic labour-intensive lacquering procedure of repeated stoving and polishing lacquer on papier-mâché with mother-of-pearl inclusions is reflected in the crosssections. Pinaceae resin and heated oil are frequently found, conform with surviving recipes. A variant of 'the old form of varnish', as historically described, was likely used. In the two pairs of wooden chairs, the lacquer layers are thinner than on the papier-mâché items. They contain copal and show different stratigraphies. These observations can be the starting point to relate technological and chemical variations to different origins. New art historical findings on lacquer production and trade in England, France and Belgium, and the study of contemporary recipes, frame the analytical results in a historical context.

This study focuses on the very beginning of lacquerware production with chinoiserie decoration in Spa from the end of the seventeenth century to the third quarter of the eighteenth century. Through an interdisciplinary approach, the historical and material-technical context of this important historical lacquer production is elucidated. Archival research was conducted along with a stylistic study of thirty objects, mainly boxes. Furthermore, seventeen of the objects from this study group were chemically analysed for their organic ingredients, pigments and metal applications.

A differential expression analysis technology developed for linear modeling of gene expression data was used in combination with thermally assisted hydrolysis and methylation gas chromatography/mass spectrometry (THM-GC/MS) to support the analysis of lacquers and varnishes on historical objects. Exudates from tropical trees, such as Manila copal, sandarac, South American copal, and Congo copal, which were frequently used in finishing layers on decorative objects up to the early 20th century, were compared through this approach. Highly discriminating features indicate biomarkers that can help to identify copals in resinous lacquers. The approach allows new, more systematic ways for finding biomarkers in the analysis of lacquered objects of art and varnishes.

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