New evidence for the intentional use of calomel as a white pigment

Mila Crippa,Paola Ricciardi,Stefano Legnaioli,Christine Kimbriel

doi:10.1002/jrs.5876

Abstract

AbstractIn this work, we report the results of the in situ application of micro‐Raman spectroscopy to the analysis of two historic painted objects: a 15th‐century illuminated manuscript and a late 16th‐century portrait miniature. Both objects were unexpectedly found to contain calomel (Hg2Cl2), intentionally used as a white pigment. Calomel was a widespread and popular medicine until it fell out of use at the end of the 19th century due to its toxicity, and a material called ‘mercury white’ is referred to in 16th‐century technical literature on painting. However, although calomel has been recognised in the past as a degradation product of cinnabar in both wall and easel paintings, its deliberate use as a pigment on cultural heritage objects has only been documented recently in white areas painted on 17th‐century South American objects. The present study describes the first ever verified use of calomel as a white pigment on European works of art, both of which predate its documented use in South America.

Highlights

The Fitzwilliam Museum in Cambridge (United Kingdom) hosts a large collection of mediaeval and Renaissance illuminated manuscripts, covering the period from the 9th to the 16th century, most of which preserve their original decoration
The protocol included Raman spectroscopy and XRF spectroscopy, the latter used both in single-point and in mapping mode. These two methods were the ones used for the identification of calomel and are further discussed here
The noninvasive analysis of two objects belonging to the Fitzwilliam Museum collection revealed some unexpected discoveries

Summary

Introduction

The Fitzwilliam Museum in Cambridge (United Kingdom) hosts a large collection of mediaeval and Renaissance illuminated manuscripts, covering the period from the 9th to the 16th century, most of which preserve their original decoration. 1565–1617), one of the most renowned ‘limners’ (miniature painters) working in London in the late 16th and early 17th century. These have recently undergone technical and scientific study, together with examples of Oliver's oeuvre from other collections. Among the Fitzwilliam's miniatures by Oliver is the portrait of a fashionably attired but unknown lady (FM 3868; see Figure 2), considered to be a typical example of his work. The recent analyses, have revealed that a large part of the white collar and lace ruff in her costume have been heavily overpainted at some point in the 18th or 19th century, covering or perhaps substituting the original pigments

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Results

Conclusion