AIC's 46th Annual Meeting

This paper will present the examination, analysis, and treatment of a seventeenth-century oil on panel painting in the collection of the Rijksmuseum in Amsterdam. The painting depicts Judith and Holofernes and was painted in 1659 by Jan de Bray, a Haarlem-based history and portrait painter. The painting was brought to the conservation department for examination and treatment in the summer of 2016. Although initial stages of the treatment were straightforward, the removal of many layers of discolored natural resin varnish revealed an unusual and confusing pattern of damage in the blue area of the bedspread. Extensive abrasions, some round and ring-shaped, were visible with the naked eye, and the presence of microscopic islands of whitish material suggested that either pigment discoloration or undesirable pigment-binder interactions had occurred. To more fully understand the damage and alterations, the blue area was subjected to intensive study. Non-invasive analytical and imaging techniques, in addition to micro-sample analysis, were employed, including infrared reflectography (IRR), Hirox digital microphotography, micro Reflectance Transformation Imaging (micro-RTI), cross-sectional analysis, macro X-Ray Fluorescence spectroscopy (MA-XRF), Scanning Electron Microscopy (SEM-BSE/EDS), Ultra High-Performance Liquid Chromatography-Photo Diode Array (UHPLC-PDA), and portable micro-Raman spectroscopy (pRaman) and X-Ray Diffractometry (pXRD). Two different blue pigments were identified: indigo was used in the first blue layer of the bedspread with lapis lazuli glazed on top. The whitish islands were characterized as lapis lazuli that were apparently degraded in the past. The authors propose a possible mechanism for the degradation of the lapis lazuli based on SEM-EDS data showing reduced levels of sulfur in the degraded areas. These data are then correlated with observations of the painting’s condition as well as with another recent publication of a painting by Hieronymus Bosch (Genbrugge 2016). Another significant finding includes the presence of alum in the indigo, which may explain the light blue fluorescence of the dark blue indigo paint under UV illumination. Consultation of contemporary source material provides additional context for the use of ultramarine and indigo pigments in seventeenth-century Dutch paintings. Ultimately, a more complete understanding of the materials present in the blue area and the ways in which later alterations to these pigments have affected the overall appearance of the painting informed the inpainting stage of treatment. This treatment step is discussed in light of these findings.