Studying the process of enamel powder preparation for émail champlevé by colour measurements and μ‐X‐ray mappings

Abstract

Colour measurements and non-destructive μ-X-ray mappings have been used for the first time in a comprehensive study of medieval émail champlevé works from different production areas in France and Germany. This approach has given a new insight into the enamel powder preparation process of the glass material used for enamelling. Colour measurements demonstrated that all production centres used glass of very similar hues, but with large differences in colour saturation. The μ-X-ray mapping results of blue enamels are described by a semi-qualitative approach. Significant variations in oxide contents of lead, cobalt, manganese and antimony oxides were found. The variations suggest that more than one glass material was used to prepare the powder for enamelling. The variations in antimony and cobalt show that glass had different degrees of opacity and colour depth. The manganese and lead contents, which do not correlate with the cobalt or antimony contents, indicate that probably glass of different base compositions was used to prepare the enamel powder for one champlevé field.

2020 atomic spectrometry update – a review of advances in X-ray fluorescence spectrometry and its special applications

“…The analysis of the different glasses used in émail champlevé provided 99 new insights into the mixing of glass for the preparation of enamel powder by high-medieval goldsmiths. Colour measurements demonstrated that all production centres used glass of very similar hues but with large differences in colour saturation.…”

Studying glass on metal: Raman analysis of medieval champlevé enamelled objects

“…[ 1,5,10 ] Further, it had been demonstrated that the glass matrix of the enamels could also show some heterogeneities at larger scale, that is, that one enamel field contains glass of different types probably due to the use of grains of crushed glass from different productions fused together. [ 11 ] Microanalytical tools, such as Raman spectroscopy, are highly adapted for the characterization of such individual glass grains in a nondestructive way and without requiring to introduce the object in an atmosphere of reduced pressure, as it is necessary for electron microscopic studies.…”

“…Most objects are parts of larger liturgical objects, and only the incense holder K 4195 is a complete object dating to the 13th c. The incense holder underwent extensive re-enamelling with enamel from industrial raw materials in the early to mid-19th c. More in-depth descriptions of the objects are provided in the literature. [11,[16][17][18][19][20][21][22][23][24]…”