From ‘Vermeer Illuminated’ to ‘The Girl in the Spotlight’: approaches and methodologies for the scientific (re-)examination of Vermeer’s Girl with a Pearl Earring

Girl with a Pearl Earring by Johannes Vermeer (c. 1665) is the most beloved painting in the collection of the Mauritshuis in The Hague, The Netherlands. The Girl was last examined during a 1994 restoration treatment, within the project Vermeer Illuminated. Conservators and scientists investigated the material composition and condition of the painting using the analytical and scientific means that were available at the time: technical photography (visible light, ultraviolet fluorescence, and infrared), X-radiography, and stereomicroscopy. To understand the build-up of the paint layers, they investigated paint samples, often mounted as cross-sections. Their results were published in the book Vermeer Illuminated (1994), and as a chapter in Vermeer Studies (1998). This paper reviews the results published in the 1990s and considers them in light of a recent research project, where new findings were made possible by advances in non-invasive imaging, chemical analysis and data science. The project The Girl in the Spotlight is a Mauritshuis initiative, and involves a team of internationally recognised specialists working within the collaborative framework of the Netherlands Institute for Conservation+Art+Science+ (NICAS), with some scientists from other institutions. In 2018, the painting was examined in front of museum visitors at the Mauritshuis. The complementary imaging techniques employed included: technical photography, multispectral infrared reflectography, reflectance and fluorescence imaging spectroscopy (hyperspectral imaging), fibre optic reflectance spectroscopy, multiscale scanning optical coherence tomography, 3D scanning, 3D digital microscopy, macroscopic X-ray fluorescence and macroscopic X-ray powder diffraction. Furthermore, the samples mounted in 1994 were re-examined, and new forms of microscopic, organic and inorganic analysis were carried out to identify the pigments and binding media. Advances in computation and data science allow the results of these techniques to be co-registered and compared, and new results to be generated. These complementary research methods have allowed the Girl in the Spotlight team to: visualise and identify materials at and beneath the surface of the painting, scan the surface topography, and examine the surface at an extremely high magnification. Ultimately, they reveal the steps Vermeer took to create the iconic image of the Girl using layers of paint and subtle optical effects. They also provide information about how the painting originally looked, and the changes that have occurred over time