Journal of Historians of Netherlandish Art

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Journal of Historians of Netherlandish Art

Methodology & Resources: New Findings from the National Gallery of Art

E. Melanie Gifford, Kathryn A. Dooley, John K. Delaney
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Footnotes
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The findings of the recent comprehensive technical study (2020–2022) of all four works by or attributed to Vermeer at the National Gallery of Art, Washington, are presented in three articles in this issue. This section offers guidance on using the JHNA image viewers and expands on the brief technical overviews in the articles with additional detail on the analytical methods used. For those who have not previously used such documents, we offer suggestions on how to interpret technical evidence. For those who regularly use such evidence in their research, the specific operating parameters of each method can be found in the endnotes of each section below. Whereas prior studies mainly relied on microanalysis of paint samples and magnified examination of the painted surface with a stereomicroscope, this study also used extensive analysis based on non-invasive chemical imaging spectroscopy, the results of which are presented in the form of images and maps, rather than graphs, making them accessible to a wider audience. Each of these methods are discussed below.

DOI: 10.5092/jhna.2022.14.2.4

The JHNA Image Viewers

The Multi-Mode Viewer

Fig. a Screenshot of JHNA IIIF multi-mode viewer with visible, false-color IRR, and XRF (Copper) images. The IIIF multi-mode viewer allows for study of high-resolution images registered to IIIF standards. Use the mouse to select up to three images from the toolbar icons, pull these layered images aside horizontally or vertically, and zoom in for a highly magnified view. Click on this image to compare any area of the painting’s surface to the same area in the false-color infrared reflectogram or the XRF map. [IIIF multi-mode viewer]

In the multi-mode viewer, using IIIF (International Image Interoperability Framework) images, the surface of the painting can be compared to the technical images, and each can be studied at increasing magnification (at times, up to a microscopic level) in “layer mode” or “side-by-side mode” (fig. a). Using this viewer, it is also possible to correlate the partially overlapped layering of brushstrokes visible on the painting’s surface to the layers of the painting (also seen in paint cross sections).

Thanks to the generosity of the University of Heidelberg’s heidICON in hosting IIIF images, all IIIF images of the National Gallery of Art Vermeer paintings can be seen in the following IIIF Manifests, and be re-used in separate image comparison in other IIIF-compatible viewers.

The Side-by-Side Viewer

Fig. b Screenshot of the JHNA side-by-side viewer [side-by-side viewer]

Using the side-by-side viewer, the reader can juxtapose any two works of art illustrated in each article, zooming in to make detailed comparisons (fig. b). Click on any of the images in the slide show below (figs. 5–27) to access this viewer. Use the icons in the toolbar to toggle between the single image viewer and the side-by-side viewer. Use the drop-down menu to compare that image to any other work of art illustrated in this article.

Interpreting Technical Evidence

Magnified Examination of the Paint Surface

Fig. c Vermeer, A Lady Writing, detail. By zooming in at high magnification below the face in A Lady Writing, we can see the blended, wet-into-wet handling of the gray ermine spots in the white fur of the jacket. Looking through the gap in the final paint between the woman’s chin and the fur, we can see a diagonal stroke of brush-furrowed underpaint below. [IIIF multi-mode viewer]

The information collected through varied analytical methods is interpreted in the context of the paintings themselves, studied at high magnification using a stereomicroscope (fig. c). The JHNA image viewers invite readers to join in this interpretation. Because it is essential to compare paint handling at the same scale, this evidence is presented throughout the articles in close details and even closer photomicrographs with scale bars that indicate the magnification.

By studying the surface of the painting at high magnification, we can see Vermeer at work. Close examination reveals individual brushstrokes and allows us to characterize the handling of paint. We often can deduce the order in which Vermeer painted individual details by looking to see whether brushstrokes lie over earlier paint that had already dried, or whether they blend wet-into-wet with the underlying brushstrokes. Examination through minute gaps in the final brushstrokes gives information on the early stages of the painting process—the ground, painted sketch, and underpaint—that can contribute to the interpretation of the technical images.

Reflectance Imaging Spectroscopy

Reflectance imaging spectroscopy (RIS) measures the amount of visible and infrared light that is reflected by artists’ materials within paint layers. Typical technical images produced from RIS analysis include material maps or false-color reflectance images.1 The articles in this issue show only high spatial resolution false-color reflectance images acquired with a different instrument in the infrared spectral region, here called false-color IRR.2

In this technique, three infrared images are assigned different colors and combined to create a false-color IRR, separating pigments more clearly than is possible with traditional infrared reflectography, which shows one infrared image in grayscale (figs. 28–31).

X-ray Fluorescence Imaging Spectroscopy

X-ray fluorescence imaging spectroscopy (XRF element mapping) measures the energy distribution of emitted X-ray radiation after excitation of the artist’s materials.3 The output technical images are maps of chemical elements, such as iron found in yellow and red ochres and lead found in lead white or lead tin yellow (figs. 32–44).

Point Analysis

In addition to mapping information across the paintings, detailed information at discrete points on the paintings was gathered through microscopic analysis of minute paint samples and through chemical spectroscopic methods that do not require samples.

Paint Cross Sections

When analyzing paint cross-sections (samples that include all layers of the paint stratigraphy), light microscopy reveals the sequence of paint and ground layers corresponding to the different stages of Vermeer’s painting process.4The visual characteristics observed in the cross section give information on the pigments present, and scanning electron microscopy with energy dispersive spectroscopy analysis (SEM-EDS) helps to identify further the specific pigments used by showing the distribution of the chemical elements (e.g., calcium, iron, lead, etc.) in the paint layers (figs. 45–47).5

These microscopic samples are removed, using eye-surgery scalpels, only from areas of existing damage; they are then mounted to show the paint layers in cross section and examined with a light microscope at up to 500x. In each sample image, the length of the scale bar (units of the numerical length) is given in micrometers (µ): one micrometer equals one thousandth of a millimeter.

Polarized Light Microscopy

Polarized light microscopy (PLM) gives detailed information on individual paint layers by identifying single pigment particles and characterizing pigment mixtures.6 Dispersed pigment samples consist of a few grains of paint collected from the paint surface without leaving a visually perceptible loss. Identifications are made by observing particles’ interactions with light in various orientations.

Point chemical spectroscopic methods

Reflectance imaging spectroscopy (RIS) can be implemented as a point measurement (gathering information from a single point on the painting). A method commonly referred to as fiber-optic reflectance spectroscopy (FORS) uses a fiber-optic probe to collect the reflected light. When X-ray fluorescence imaging spectroscopy is implemented as a point measurement, the technique is commonly referred to as X-ray fluorescence (XRF) analysis.

E. Melanie Gifford currently holds a J. Clawson Mills Scholarship at the Metropolitan Museum of Art and is writing a book on visual strategies of seventeenth-century Dutch naturalistic landscape. Previously, she held positions in scientific research at the National Gallery of Art and in painting conservation at the Walters Art Museum. Recent publications explored Rubens’s The Fall of Phaeton (JHNA 2019) and high-life genre specialists (with Lisha Deming Glinsman, in Vermeer and the Masters of Genre Painting: Inspiration and Rivalry, 2017).

e.melanie.gifford@gmail.com

Kathryn A. Dooley is an imaging scientist in the scientific research department at the National Gallery of Art. Her research focuses on spectroscopic techniques that allow for the identification and mapping of many artists’ materials without requiring a sample. She was part of an in-depth study on Vermeer’s Girl with a Pearl Earring that resulted in a series of articles about his painted underlayers and pigment distributions (Heritage Science 2019 and 2020).

k-dooley@nga.gov

John K. Delaney is a senior imaging scientist and supervisor in the scientific research department at the National Gallery of Art. His research focuses on the adaptation of remote sensors and processing methods to study of works of art. He is an affiliated faculty member in the Center for Imaging Science at Rochester Institute of Technology and an associate editor for the American Association for the Advancement of Science journal Science Advances. He was part of an in-depth study on Vermeer’s Girl with a Pearl Earring that resulted in a series of articles in Heritage Science in 2019 and 2020.

j-delaney@nga.gov

Fig. a Screenshot of JHNA IIIF multi-mode viewer with visible, false-color IRR, and XRF (Copper) images. The IIIF multi-mode viewer allows for study of high-resolution images registered to IIIF standards. Use the mouse to select up to three images from the toolbar icons, pull these layered images aside horizontally or vertically, and zoom in for a highly magnified view. Click on this image to compare any area of the painting’s surface to the same area in the false-color infrared reflectogram or the XRF map. [IIIF multi-mode viewer]
Johannes Vermeer, A Lady Writing, ca. 1665, oil on canvas, National Gallery of Art, Washington
Fig. 1 Johannes Vermeer, A Lady Writing, ca. 1665, oil on canvas, 45 x 39.9 cm. National Gallery of Art, Washington, DC, Gift of Harry Waldron Havemeyer and Horace Havemeyer, Jr., in memory of their father, Horace Havemeyer, inv. 1962.10.1 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Johannes Vermeer, Woman Holding a Balance, ca. 1664, oil on canvas, National Gallery of Art, Washington
Fig. 2 Johannes Vermeer, Woman Holding a Balance, ca. 1664, oil on canvas, 39.7 x 35.5 cm. National Gallery of Art, Washington, DC, Widener Collection, inv. 1942.9.97 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Johannes Vermeer, Girl with the Red Hat, ca. 1669, oil on panel, National Gallery of Art, Washington
Fig. 3 Johannes Vermeer, Girl with the Red Hat, ca. 1669, oil on panel, 22.8 x 18 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.53 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Studio of Johannes Vermeer, Girl with a Flute, ca. 1669/1675, oil on panel, National Gallery of Art, Washington
Fig. 4 Studio of Johannes Vermeer, Girl with a Flute, ca.  1669/1675, oil on panel, 20 x 17.8 cm. National Gallery of Art, Washington, DC, Widener Collection, inv. 1942.9.98 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Fig. b Screenshot of the JHNA side-by-side viewer [side-by-side viewer]
Frans van Mieris, Brothel Scene, ca. 1658–1659, oil on panel, Mauritshuis, The Hague
Fig. 5 Frans van Mieris, Brothel Scene, ca. 1658–1659, oil on panel, 42.5 x 33.3 cm. Mauritshuis, The Hague, inv. 860 (artwork in the public domain) [side-by-side viewer]
Gabriel Metsu, The Intruder, ca. 1660, oil on panel, National Gallery of Art, Washington
Fig. 6 Gabriel Metsu, The Intruder, ca. 1660, oil on panel, 66.6 x 59.4 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.57 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Milkmaid, ca. 1660, oil on canvas, Rijksmuseum, Amsterdam
Fig. 7 Johannes Vermeer, The Milkmaid, ca. 1660, oil on canvas, 45.5 x 41 cm. Rijksmuseum, Amsterdam, inv. SK-A-2344 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, National Gallery of Ireland, Dublin
Fig. 8 Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, 71.1 x 60.5 cm. National Gallery of Ireland, Dublin, Presented, Sir Alfred and Lady Beit, 1987 (Beit Collection), inv. NGI.4535. Photo © National Gallery of Ireland (artwork in the public domain) [side-by-side viewer]
Gabriel Metsu, Woman Reading a Letter, 1664–1666, oil on panel, National Gallery of Ireland, Dublin
Fig. 9 Gabriel Metsu, Woman Reading a Letter, 1664–1666, oil on panel, 52.5 x 40.2 cm. National Gallery of Ireland, Dublin, Presented, Sir Alfred and Lady Beit, 1987 (Beit Collection), inv. NGI.4537. Photo © National Gallery of Ireland (artwork in the public domain) [side-by-side viewer]
Gerard ter Borch, Woman Writing a Letter, 1655, oil on panel, Mauritshuis, The Hague
Fig. 10 Gerard ter Borch, Woman Writing a Letter, 1655, oil on panel, 38.3 x 27.9 cm. Mauritshuis, The Hague, inv. 797 (artwork in the public domain) [side-by-side viewer]
Rembrandt van Rijn, Self-Portrait, ca. 1628, oil on panel, Rijksmuseum, Amsterdam
Fig. 11 Rembrandt van Rijn, Self-Portrait, ca. 1628, oil on panel, 22.6 cm x 18.7 cm. Rijksmuseum, Amsterdam, inv. SK-A-4691 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Girl with a Pearl Earring, ca. 1665, oil on canvas, Mauritshuis, The Hague
Fig. 12 Johannes Vermeer, Girl with a Pearl Earring, ca. 1665, oil on canvas, 44.5 x 39 cm. Mauritshuis, The Hague, inv. 670 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Study of a Young Woman, ca. 1665−67, oil on canvas, The Metropolitan Museum of Art, New York
Fig. 13 Johannes Vermeer, Study of a Young Woman, ca. 1665−67, oil on canvas, 44.5 x 40 cm. The Metropolitan Museum of Art, New York, Gift of Mr. and Mrs. Charles Wrightsman, in memory of Theodore Rousseau Jr., inv. 1979.396.1.(artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, A Maid Asleep, ca. 1656–57, oil on canvas, The Metropolitan Museum of Art, New York
Fig. 14 Johannes Vermeer, A Maid Asleep, ca. 1656–57, oil on canvas, 87.6 x 76.5 cm. The Metropolitan Museum of Art, New York, Bequest of Benjamin Altman, 1913, inv. 14.40.611 (artwork in the public domain) [side-by-side viewer]
Michiel Sweerts, A Young Maidservant, ca. 1660, oil on canvas, The Kremer Collection
Fig. 15 Michiel Sweerts, A Young Maidservant, ca. 1660, oil on canvas, 61 x 53.5 cm. The Kremer Collection [side-by-side viewer]
Michiel Sweerts, Boy in a Turban Holding a Nosegay, ca. 1658–1661, oil on canvas, Museo Nacional Thyssen-Bornemisza, Madrid
Fig. 16 Michiel Sweerts, Boy in a Turban Holding a Nosegay, ca. 1658–1661, oil on canvas. 76.4 x 61.8 cm. © Museo Nacional Thyssen-Bornemisza, Madrid, inv. 385 (1981.19) [side-by-side viewer]
Johannes Vermeer, The Lacemaker, ca. 1669−1670, oil on canvas (attached to panel),Musée du Louvre, Paris
Fig. 17 Johannes Vermeer, The Lacemaker, ca. 1669−1670, oil on canvas (attached to panel), 23.9 x 20.5 cm. Musée du Louvre, Paris, inv. M.I. 1448. Musée du Louvre, Paris / Art Resource, NY (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Young Woman Seated at a Virginal, ca. 1670−72, oil on canvas, The Leiden Collection, New York
Fig. 18 Johannes Vermeer, Young Woman Seated at a Virginal, ca. 1670−72, oil on canvas, painted surface measures 24.7 x 19.4 cm (the tacking margins have been removed), The Leiden Collection, New York, inv. JVe-100. Image courtesy of the Leiden Collection, New York (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Mistress and Maid, ca. 1666−1667, oil on canvas, Frick Collection, New York
Fig. 19 Johannes Vermeer, Mistress and Maid, ca. 1666−1667, oil on canvas, 90.2 x 78.7 cm. Frick Collection, New York, Henry Clay Frick Bequest, inv. 1919.1.126. © The Frick Collection (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, National Gallery of Ireland, Dublin
Fig. 20 Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, 71.1 x 60.5 cm. National Gallery of Ireland, Dublin, Presented, Sir Alfred and Lady Beit, 1987 (Beit Collection), inv. NGI.4537. Photo © National Gallery of Ireland (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Astronomer, 1668, oil on canvas, Musée du Louvre, Paris
Fig. 21 Johannes Vermeer, The Astronomer, 1668, oil on canvas, 51 x 45 cm. Musée du Louvre, Paris, inv. RF 1983 28. Musée du Louvre, Paris / Art Resource, NY (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Geographer, 1669, oil on canvas, Städel Museum, Frankfurt am Main
Fig. 22 Johannes Vermeer, The Geographer, 1669, oil on canvas, 51.6 x 45.4 cm. Städel Museum, Frankfurt am Main, inv. 1149 (artwork in the public domain)a [side-by-side viewer]
Imitator of Johannes Vermeer, The Lacemaker, ca. 1925, oil on canvas, National Gallery of Art, Washington
Fig. 23 Imitator of Johannes Vermeer, The Lacemaker, ca. 1925, oil on canvas, 44.5 x 40 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.54 (artwork in the public domain) [side-by-side viewer]
Imitator of Johannes Vermeer, The Smiling Girl, ca. 1925, oil on canvas, National Gallery of Art, Washington
Fig. 24 Imitator of Johannes Vermeer, The Smiling Girl, ca. 1925, oil on canvas, 41 x 31.8 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.55 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Girl with the Wine Glass, 1658/1659, oil on canvas, Herzog Anton Ulrich Museum, Braunschweig
Fig. 25 Johannes Vermeer, The Girl with the Wine Glass, 1658/1659, oil on canvas, 77.5 x 66.7 cm. Herzog Anton Ulrich Museum, Braunschweig, inv. GG 316. Herzog Anton Ulrich Museum, Braunschweig / Art Resources, NY (artwork in the public domain) [side-by-side viewer]
Cornelis de Man, Geographers at Work, ca. 1670, oil on canvas, Hamburger Kunsthalle, Hamburg
Fig. 26 Cornelis de Man, Geographers at Work, ca. 1670, oil on canvas, 81 x 68 cm. Hamburger Kunsthalle, Hamburg, inv. HK-239. bpk bildagentur/Hamburger Kunsthalle/Elke Walford/Art Resource, NY (artwork in the public domain) [side-by-side viewer]
Attributed to Johannes Vermeer, Saint Praxedis, 1655, oil on canvas, National Museum of Western Art, Tokyo
Fig. 27 Attributed to Johannes Vermeer, Saint Praxedis, 1655, oil on canvas, 101.6 x 82.6 cm. National Museum of Western Art, Tokyo, inv. DEP.2014-0001 [side-by-side viewer]
Fig. c Vermeer, A Lady Writing, detail. By zooming in at high magnification below the face in A Lady Writing, we can see the blended, wet-into-wet handling of the gray ermine spots in the white fur of the jacket. Looking through the gap in the final paint between the woman’s chin and the fur, we can see a diagonal stroke of brush-furrowed underpaint below. [IIIF multi-mode viewer]
Vermeer, A Lady Writing, false-color IRR
Fig. 28 Vermeer, A Lady Writing (fig. 1), false-color IRR [IIIF multi-mode viewer]
Vermeer, Woman Holding a Balance, false-color IRR
Fig. 29 Vermeer, Woman Holding a Balance (fig. 2), false-color IRR [IIIF multi-mode viewer]
Vermeer, Girl with the Red Hat, false-color IRR
Fig. 30 Vermeer, Girl with the Red Hat (fig. 3), false-color IRR [IIIF multi-mode viewer]
Fig. 31 Vermeer, Girl with a Flute (fig. 4), false-color IRR [IIIF multi-mode viewer]
Fig. 32 Vermeer, A Lady Writing (fig. 1), in the XRF copper map (Cu K, gamma adjusted), white areas map the presence of copper, which here corresponds to a drier in the underpaint. In Vermeer’s first version of the composition, the woman held her pen almost vertically; the XRF copper map confirms this, showing that in the underpaint the background was brushed up to the margins of the vertical quill, leaving a narrow reserve for the original form. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 33 Vermeer, A Lady Writing (fig. 1), the XRF iron map (Fe K) helps to visualize the iron-rich ochre underpaint layer. In the underpaint stage, Vermeer dragged a wide brush through the still-wet ochre, wiping away paint to leave a few wide troughs that created just a summary indication of folds. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 34 Vermeer, A Lady Writing (fig. 1), the XRF lead map for the L-line energy (Pb L), which corresponds to lead in all layers of the painting, shows the quill held vertically in the underpaint, as well as the relaxed, final position of the pen. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 35 Vermeer, A Lady Writing (fig. 1), the XRF lead map for the M-line energy (Pb M) which records lead white pigment mainly in surface paint, shows the smoothly modeled highlights of the final image. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 36 Vermeer, A Lady Writing (fig. 1), the XRF map for tin (Sn L) shows the texture of stippled brushmarks where the underpaint of the tablecloth includes highlights based on lead-tin yellow. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 37 Vermeer, Woman Holding a Balance (fig. 2), in the XRF copper map (Cu K), white areas map the presence of copper—which here corresponds to a drier in the underpaint—while darker or black areas correspond to little or no signal for copper (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 38 Vermeer, Woman Holding a Balance (fig. 2), XRF copper map (Cu K) is here showninverted so that the darkest areas correspond to the greatest amount of copper, where the copper-containing underpaint must have been most heavily applied (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 39 Vermeer, Girl with the Red Hat (fig. 3), in the XRF copper map (Cu K), white areas map the presence of copper—which here corresponds to a drier used in Vermeer’s image of the woman and also in the underlying image of a man with a large hat that lies below (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 40 Vermeer, Girl with the Red Hat (fig. 3), the XRF manganese map (Mn K) reveals the use of an umber-based painted sketch that laid out the underlying composition of a man. Many blackish areas in manganese map correspond to dense paints applied in later stages (e.g., the man’s face and the yellow highlights of the girl’s cloak) that suppress the signal from the manganese-containing paint below. (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 41 Vermeer, Girl with the Red Hat (fig. 3),  the XRF lead map for the L-line energy (Pb L), which corresponds to lead in all layers of the painting, shows elements based on lead white in the underlying image (the man’s face and collar) as well as in the final image (the face of the girl and highlights on the cloak). (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 42 Vermeer, Girl with the Red Hat (fig. 3), the XRF tin map (Sn L) records the pattern of the yellow highlights on the cloak, which are based on lead-tin yellow pigment. (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 43 Vermeer, Girl with the Red Hat (fig. 3),  the XRF mercury map (Hg) (histogram stretched and gamma adjusted to show low amounts of mercury) corresponds to the red pigment, vermilion. The map shows a fainter mercury signal corresponding to the underpaint, where Vermeer seems to have just roughed out the hat with a few wild brushstrokes that extend beyond the hat’s final contours at the upper left. The brightest signal coincides with the finished hat, its outer contour varied by tiny feathery strokes of vermilion. (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 44 Vermeer, Girl with a Flute (fig. 4), in the XRF copper map (Cu K), white areas map the presence of copper—which here corresponds to a drier in the underpaint—while darker or black areas correspond to little or no signal for copper (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 45 Vermeer, A Lady Writing, paint cross section taken from tablecloth, with smoothly brushed, dark final paint (3) over a textured lead-tin yellow–rich paint mixture corresponding to a half-light in the underpaint (2) and the ground (1) [IIIF multi-mode viewer]
Fig. 46 Vermeer, Woman Holding a Balance, paint cross section from the tablecloth shown in autofluorescence (excitation: bandpass filter 355-425 nm; transmission: long pass filter 470 nm). The sample is marked with the diagonal path of a SEM-EDS line scan for copper through three layers: repaint, final paint, and underpaint (the ground is not included in this sample). [IIIF multi-mode viewer]
Fig. 47 Vermeer, Girl with a Flute, paint cross section taken from a loss in the face (exposed during treatment in 1994). Vermilion particles, visible throughout both paint layers, measure up to 4 µm in the final paint (4), and under 2 µm in the underpaint (3). The paint layers lie over the upper ground (2) and a trace of the lower ground (1). [IIIF multi-mode viewer]
Fig. 48 Vermeer, Woman Holding a Balance, dispersed pigment sample of the brown painted sketch (photographed with slightly uncrossed polars). The sample includes isotropic dark brown particles consistent with umber, and almost no black pigment, as well as fragments of the ground, in which lead white and calcium carbonate appear as brightly lit (birefringent) particles. [IIIF multi-mode viewer]
Fig. 49 Vermeer, A Lady Writing, dispersed pigment sample showing coarsely ground lead-tin yellow pigment in the underpaint of the lighted tablecloth (photographed with slightly uncrossed polars). The sample also includes smaller amounts of ultramarine blue, lead white and calcium carbonate. [IIIF multi-mode viewer]
Fig. 50 Vermeer, A Lady Writing, dispersed pigment sample showing more finely ground lead-tin yellow pigment in the final paint of a midtone highlight on the yellow  jacket (photographed with slightly uncrossed polars). The sample also includes calcium carbonate and a small amount of isotropic brown earth. [IIIF multi-mode viewer]
Fig. 51 Vermeer, Girl with the Red Hat, dispersed pigment sample of greenish shadow from the face that includes yellow earth and isotropic brown earth with large, deep blue-green particles of green earth (white arrow) (photographed with slightly uncrossed polars). The sample also includes minor amounts of minor amounts of white lead, vermilion, and traces of black and red lake. [IIIF multi-mode viewer]
Fig. 52 Vermeer, Girl with a Flute, dispersed pigment sample of greenish shadow from the face, with small, pale pigment particles of green earth (white arrows) and a substantial proportion of large, glassy particles (black arrows) (photographed with slightly uncrossed polars). The sample also includes yellow earth, brown earth, a minor amount of black, and traces of white lead and vermilion. [IIIF multi-mode viewer]

  1. 1. Two hyperspectral reflectance imaging instruments were used, one sensitive from 400 to 950 nm (2.5 nm spectral sampling) and the other from 1000 to 2450 nm (2.8 nm sampling). In each case, the spatial sampling at the paintings was 0.2 mm per pixel. The analysis of the RIS image cubes was done using ENVI (L3 Harris) after mosaicking and image registration to a reference color image using in-house software tools.

  2. 2. Multispectral infrared reflectance images were collected with a custom infrared camera consisting of a cooled infrared detector array (indium antimonide, 1280 x 1024 detectors, IRCameras), a custom infrared lens (Stingray Optics), and one of three possible spectral filters (1100 to 1400 nm, 1500 to 1800 nm, or 2100 to 2450 nm). The spatial sampling at the painting was 0.045 mm per pixel. The resulting images were mosaicked and registered to a reference color image using in-house software tools.

  3. 3. A custom XRF instrument was used consisting of a rhodium source with a converging capillary optic (XOS) operated at 50kV and 0.75 mA. The resulting X-ray emission was measured using a silicon drift detector (XG-Labs) with an effective detector area of 50mm2 and a digital pulse processor. The collection conditions were a 0.25 mm spot size at the painting, a pixel dwell time of 0.05 sec, and a scan speed of 5 mm per second. Image registration of the XRF image cube to a reference color image was done using in-house software tools. The chemical element maps were generated by fitting the registered XRF image cube using Pymca software (European Synchrotron Radiation Facility).

  4. 4. Paint cross section samples were mounted in polyester resin and then ground and polished to expose the layers. Mounted samples were examined using a Leica DMRX research microscope with incident illumination using both visible light and autofluorescence at magnifications up to 500x.

  5. 5. Uncoated samples were examined using a Hitachi S-3400N scanning electron microscope with tungsten filament operating at 20 kV in variable pressure mode at 30 to 40 Pa at a distance of 10 mm from sample to detector. Elemental data was acquired using an Oxford Instruments 80mm2 SSD detector and Aztec 300 spectrometer and software package. Elemental data was corroborated by visual characteristics observed in the cross section.

  6. 6. Dispersed pigment samples were mounted in Cargille Meltmount (n=1.66) for microscopic examination in transmitted light. Mounted slides were examined using a Leica DMRX polarizing light research microscope at up to 500x magnification.

List of Illustrations

Fig. a Screenshot of JHNA IIIF multi-mode viewer with visible, false-color IRR, and XRF (Copper) images. The IIIF multi-mode viewer allows for study of high-resolution images registered to IIIF standards. Use the mouse to select up to three images from the toolbar icons, pull these layered images aside horizontally or vertically, and zoom in for a highly magnified view. Click on this image to compare any area of the painting’s surface to the same area in the false-color infrared reflectogram or the XRF map. [IIIF multi-mode viewer]
Johannes Vermeer, A Lady Writing, ca. 1665, oil on canvas, National Gallery of Art, Washington
Fig. 1 Johannes Vermeer, A Lady Writing, ca. 1665, oil on canvas, 45 x 39.9 cm. National Gallery of Art, Washington, DC, Gift of Harry Waldron Havemeyer and Horace Havemeyer, Jr., in memory of their father, Horace Havemeyer, inv. 1962.10.1 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Johannes Vermeer, Woman Holding a Balance, ca. 1664, oil on canvas, National Gallery of Art, Washington
Fig. 2 Johannes Vermeer, Woman Holding a Balance, ca. 1664, oil on canvas, 39.7 x 35.5 cm. National Gallery of Art, Washington, DC, Widener Collection, inv. 1942.9.97 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Johannes Vermeer, Girl with the Red Hat, ca. 1669, oil on panel, National Gallery of Art, Washington
Fig. 3 Johannes Vermeer, Girl with the Red Hat, ca. 1669, oil on panel, 22.8 x 18 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.53 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Studio of Johannes Vermeer, Girl with a Flute, ca. 1669/1675, oil on panel, National Gallery of Art, Washington
Fig. 4 Studio of Johannes Vermeer, Girl with a Flute, ca.  1669/1675, oil on panel, 20 x 17.8 cm. National Gallery of Art, Washington, DC, Widener Collection, inv. 1942.9.98 (artwork in the public domain) Click on the image to compare images (visible light, false-color IRR, XRF copper map). [IIIF multi-mode viewer]
Fig. b Screenshot of the JHNA side-by-side viewer [side-by-side viewer]
Frans van Mieris, Brothel Scene, ca. 1658–1659, oil on panel, Mauritshuis, The Hague
Fig. 5 Frans van Mieris, Brothel Scene, ca. 1658–1659, oil on panel, 42.5 x 33.3 cm. Mauritshuis, The Hague, inv. 860 (artwork in the public domain) [side-by-side viewer]
Gabriel Metsu, The Intruder, ca. 1660, oil on panel, National Gallery of Art, Washington
Fig. 6 Gabriel Metsu, The Intruder, ca. 1660, oil on panel, 66.6 x 59.4 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.57 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Milkmaid, ca. 1660, oil on canvas, Rijksmuseum, Amsterdam
Fig. 7 Johannes Vermeer, The Milkmaid, ca. 1660, oil on canvas, 45.5 x 41 cm. Rijksmuseum, Amsterdam, inv. SK-A-2344 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, National Gallery of Ireland, Dublin
Fig. 8 Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, 71.1 x 60.5 cm. National Gallery of Ireland, Dublin, Presented, Sir Alfred and Lady Beit, 1987 (Beit Collection), inv. NGI.4535. Photo © National Gallery of Ireland (artwork in the public domain) [side-by-side viewer]
Gabriel Metsu, Woman Reading a Letter, 1664–1666, oil on panel, National Gallery of Ireland, Dublin
Fig. 9 Gabriel Metsu, Woman Reading a Letter, 1664–1666, oil on panel, 52.5 x 40.2 cm. National Gallery of Ireland, Dublin, Presented, Sir Alfred and Lady Beit, 1987 (Beit Collection), inv. NGI.4537. Photo © National Gallery of Ireland (artwork in the public domain) [side-by-side viewer]
Gerard ter Borch, Woman Writing a Letter, 1655, oil on panel, Mauritshuis, The Hague
Fig. 10 Gerard ter Borch, Woman Writing a Letter, 1655, oil on panel, 38.3 x 27.9 cm. Mauritshuis, The Hague, inv. 797 (artwork in the public domain) [side-by-side viewer]
Rembrandt van Rijn, Self-Portrait, ca. 1628, oil on panel, Rijksmuseum, Amsterdam
Fig. 11 Rembrandt van Rijn, Self-Portrait, ca. 1628, oil on panel, 22.6 cm x 18.7 cm. Rijksmuseum, Amsterdam, inv. SK-A-4691 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Girl with a Pearl Earring, ca. 1665, oil on canvas, Mauritshuis, The Hague
Fig. 12 Johannes Vermeer, Girl with a Pearl Earring, ca. 1665, oil on canvas, 44.5 x 39 cm. Mauritshuis, The Hague, inv. 670 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Study of a Young Woman, ca. 1665−67, oil on canvas, The Metropolitan Museum of Art, New York
Fig. 13 Johannes Vermeer, Study of a Young Woman, ca. 1665−67, oil on canvas, 44.5 x 40 cm. The Metropolitan Museum of Art, New York, Gift of Mr. and Mrs. Charles Wrightsman, in memory of Theodore Rousseau Jr., inv. 1979.396.1.(artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, A Maid Asleep, ca. 1656–57, oil on canvas, The Metropolitan Museum of Art, New York
Fig. 14 Johannes Vermeer, A Maid Asleep, ca. 1656–57, oil on canvas, 87.6 x 76.5 cm. The Metropolitan Museum of Art, New York, Bequest of Benjamin Altman, 1913, inv. 14.40.611 (artwork in the public domain) [side-by-side viewer]
Michiel Sweerts, A Young Maidservant, ca. 1660, oil on canvas, The Kremer Collection
Fig. 15 Michiel Sweerts, A Young Maidservant, ca. 1660, oil on canvas, 61 x 53.5 cm. The Kremer Collection [side-by-side viewer]
Michiel Sweerts, Boy in a Turban Holding a Nosegay, ca. 1658–1661, oil on canvas, Museo Nacional Thyssen-Bornemisza, Madrid
Fig. 16 Michiel Sweerts, Boy in a Turban Holding a Nosegay, ca. 1658–1661, oil on canvas. 76.4 x 61.8 cm. © Museo Nacional Thyssen-Bornemisza, Madrid, inv. 385 (1981.19) [side-by-side viewer]
Johannes Vermeer, The Lacemaker, ca. 1669−1670, oil on canvas (attached to panel),Musée du Louvre, Paris
Fig. 17 Johannes Vermeer, The Lacemaker, ca. 1669−1670, oil on canvas (attached to panel), 23.9 x 20.5 cm. Musée du Louvre, Paris, inv. M.I. 1448. Musée du Louvre, Paris / Art Resource, NY (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Young Woman Seated at a Virginal, ca. 1670−72, oil on canvas, The Leiden Collection, New York
Fig. 18 Johannes Vermeer, Young Woman Seated at a Virginal, ca. 1670−72, oil on canvas, painted surface measures 24.7 x 19.4 cm (the tacking margins have been removed), The Leiden Collection, New York, inv. JVe-100. Image courtesy of the Leiden Collection, New York (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Mistress and Maid, ca. 1666−1667, oil on canvas, Frick Collection, New York
Fig. 19 Johannes Vermeer, Mistress and Maid, ca. 1666−1667, oil on canvas, 90.2 x 78.7 cm. Frick Collection, New York, Henry Clay Frick Bequest, inv. 1919.1.126. © The Frick Collection (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, National Gallery of Ireland, Dublin
Fig. 20 Johannes Vermeer, Woman Writing a Letter, with her Maid, ca. 1670, oil on canvas, 71.1 x 60.5 cm. National Gallery of Ireland, Dublin, Presented, Sir Alfred and Lady Beit, 1987 (Beit Collection), inv. NGI.4537. Photo © National Gallery of Ireland (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Astronomer, 1668, oil on canvas, Musée du Louvre, Paris
Fig. 21 Johannes Vermeer, The Astronomer, 1668, oil on canvas, 51 x 45 cm. Musée du Louvre, Paris, inv. RF 1983 28. Musée du Louvre, Paris / Art Resource, NY (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Geographer, 1669, oil on canvas, Städel Museum, Frankfurt am Main
Fig. 22 Johannes Vermeer, The Geographer, 1669, oil on canvas, 51.6 x 45.4 cm. Städel Museum, Frankfurt am Main, inv. 1149 (artwork in the public domain)a [side-by-side viewer]
Imitator of Johannes Vermeer, The Lacemaker, ca. 1925, oil on canvas, National Gallery of Art, Washington
Fig. 23 Imitator of Johannes Vermeer, The Lacemaker, ca. 1925, oil on canvas, 44.5 x 40 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.54 (artwork in the public domain) [side-by-side viewer]
Imitator of Johannes Vermeer, The Smiling Girl, ca. 1925, oil on canvas, National Gallery of Art, Washington
Fig. 24 Imitator of Johannes Vermeer, The Smiling Girl, ca. 1925, oil on canvas, 41 x 31.8 cm. National Gallery of Art, Washington, DC, Andrew W. Mellon Collection, inv. 1937.1.55 (artwork in the public domain) [side-by-side viewer]
Johannes Vermeer, The Girl with the Wine Glass, 1658/1659, oil on canvas, Herzog Anton Ulrich Museum, Braunschweig
Fig. 25 Johannes Vermeer, The Girl with the Wine Glass, 1658/1659, oil on canvas, 77.5 x 66.7 cm. Herzog Anton Ulrich Museum, Braunschweig, inv. GG 316. Herzog Anton Ulrich Museum, Braunschweig / Art Resources, NY (artwork in the public domain) [side-by-side viewer]
Cornelis de Man, Geographers at Work, ca. 1670, oil on canvas, Hamburger Kunsthalle, Hamburg
Fig. 26 Cornelis de Man, Geographers at Work, ca. 1670, oil on canvas, 81 x 68 cm. Hamburger Kunsthalle, Hamburg, inv. HK-239. bpk bildagentur/Hamburger Kunsthalle/Elke Walford/Art Resource, NY (artwork in the public domain) [side-by-side viewer]
Attributed to Johannes Vermeer, Saint Praxedis, 1655, oil on canvas, National Museum of Western Art, Tokyo
Fig. 27 Attributed to Johannes Vermeer, Saint Praxedis, 1655, oil on canvas, 101.6 x 82.6 cm. National Museum of Western Art, Tokyo, inv. DEP.2014-0001 [side-by-side viewer]
Fig. c Vermeer, A Lady Writing, detail. By zooming in at high magnification below the face in A Lady Writing, we can see the blended, wet-into-wet handling of the gray ermine spots in the white fur of the jacket. Looking through the gap in the final paint between the woman’s chin and the fur, we can see a diagonal stroke of brush-furrowed underpaint below. [IIIF multi-mode viewer]
Vermeer, A Lady Writing, false-color IRR
Fig. 28 Vermeer, A Lady Writing (fig. 1), false-color IRR [IIIF multi-mode viewer]
Vermeer, Woman Holding a Balance, false-color IRR
Fig. 29 Vermeer, Woman Holding a Balance (fig. 2), false-color IRR [IIIF multi-mode viewer]
Vermeer, Girl with the Red Hat, false-color IRR
Fig. 30 Vermeer, Girl with the Red Hat (fig. 3), false-color IRR [IIIF multi-mode viewer]
Fig. 31 Vermeer, Girl with a Flute (fig. 4), false-color IRR [IIIF multi-mode viewer]
Fig. 32 Vermeer, A Lady Writing (fig. 1), in the XRF copper map (Cu K, gamma adjusted), white areas map the presence of copper, which here corresponds to a drier in the underpaint. In Vermeer’s first version of the composition, the woman held her pen almost vertically; the XRF copper map confirms this, showing that in the underpaint the background was brushed up to the margins of the vertical quill, leaving a narrow reserve for the original form. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 33 Vermeer, A Lady Writing (fig. 1), the XRF iron map (Fe K) helps to visualize the iron-rich ochre underpaint layer. In the underpaint stage, Vermeer dragged a wide brush through the still-wet ochre, wiping away paint to leave a few wide troughs that created just a summary indication of folds. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 34 Vermeer, A Lady Writing (fig. 1), the XRF lead map for the L-line energy (Pb L), which corresponds to lead in all layers of the painting, shows the quill held vertically in the underpaint, as well as the relaxed, final position of the pen. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 35 Vermeer, A Lady Writing (fig. 1), the XRF lead map for the M-line energy (Pb M) which records lead white pigment mainly in surface paint, shows the smoothly modeled highlights of the final image. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 36 Vermeer, A Lady Writing (fig. 1), the XRF map for tin (Sn L) shows the texture of stippled brushmarks where the underpaint of the tablecloth includes highlights based on lead-tin yellow. (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 37 Vermeer, Woman Holding a Balance (fig. 2), in the XRF copper map (Cu K), white areas map the presence of copper—which here corresponds to a drier in the underpaint—while darker or black areas correspond to little or no signal for copper (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 38 Vermeer, Woman Holding a Balance (fig. 2), XRF copper map (Cu K) is here showninverted so that the darkest areas correspond to the greatest amount of copper, where the copper-containing underpaint must have been most heavily applied (photo: Dooley et al., "Comparing Vermeer's Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 39 Vermeer, Girl with the Red Hat (fig. 3), in the XRF copper map (Cu K), white areas map the presence of copper—which here corresponds to a drier used in Vermeer’s image of the woman and also in the underlying image of a man with a large hat that lies below (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 40 Vermeer, Girl with the Red Hat (fig. 3), the XRF manganese map (Mn K) reveals the use of an umber-based painted sketch that laid out the underlying composition of a man. Many blackish areas in manganese map correspond to dense paints applied in later stages (e.g., the man’s face and the yellow highlights of the girl’s cloak) that suppress the signal from the manganese-containing paint below. (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 41 Vermeer, Girl with the Red Hat (fig. 3),  the XRF lead map for the L-line energy (Pb L), which corresponds to lead in all layers of the painting, shows elements based on lead white in the underlying image (the man’s face and collar) as well as in the final image (the face of the girl and highlights on the cloak). (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 42 Vermeer, Girl with the Red Hat (fig. 3), the XRF tin map (Sn L) records the pattern of the yellow highlights on the cloak, which are based on lead-tin yellow pigment. (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 43 Vermeer, Girl with the Red Hat (fig. 3),  the XRF mercury map (Hg) (histogram stretched and gamma adjusted to show low amounts of mercury) corresponds to the red pigment, vermilion. The map shows a fainter mercury signal corresponding to the underpaint, where Vermeer seems to have just roughed out the hat with a few wild brushstrokes that extend beyond the hat’s final contours at the upper left. The brightest signal coincides with the finished hat, its outer contour varied by tiny feathery strokes of vermilion. (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 44 Vermeer, Girl with a Flute (fig. 4), in the XRF copper map (Cu K), white areas map the presence of copper—which here corresponds to a drier in the underpaint—while darker or black areas correspond to little or no signal for copper (photo: Dooley et al., “Documenting the Painting Techniques,” https://heritagesciencejournal.springeropen.com/) [IIIF multi-mode viewer]
Fig. 45 Vermeer, A Lady Writing, paint cross section taken from tablecloth, with smoothly brushed, dark final paint (3) over a textured lead-tin yellow–rich paint mixture corresponding to a half-light in the underpaint (2) and the ground (1) [IIIF multi-mode viewer]
Fig. 46 Vermeer, Woman Holding a Balance, paint cross section from the tablecloth shown in autofluorescence (excitation: bandpass filter 355-425 nm; transmission: long pass filter 470 nm). The sample is marked with the diagonal path of a SEM-EDS line scan for copper through three layers: repaint, final paint, and underpaint (the ground is not included in this sample). [IIIF multi-mode viewer]
Fig. 47 Vermeer, Girl with a Flute, paint cross section taken from a loss in the face (exposed during treatment in 1994). Vermilion particles, visible throughout both paint layers, measure up to 4 µm in the final paint (4), and under 2 µm in the underpaint (3). The paint layers lie over the upper ground (2) and a trace of the lower ground (1). [IIIF multi-mode viewer]
Fig. 48 Vermeer, Woman Holding a Balance, dispersed pigment sample of the brown painted sketch (photographed with slightly uncrossed polars). The sample includes isotropic dark brown particles consistent with umber, and almost no black pigment, as well as fragments of the ground, in which lead white and calcium carbonate appear as brightly lit (birefringent) particles. [IIIF multi-mode viewer]
Fig. 49 Vermeer, A Lady Writing, dispersed pigment sample showing coarsely ground lead-tin yellow pigment in the underpaint of the lighted tablecloth (photographed with slightly uncrossed polars). The sample also includes smaller amounts of ultramarine blue, lead white and calcium carbonate. [IIIF multi-mode viewer]
Fig. 50 Vermeer, A Lady Writing, dispersed pigment sample showing more finely ground lead-tin yellow pigment in the final paint of a midtone highlight on the yellow  jacket (photographed with slightly uncrossed polars). The sample also includes calcium carbonate and a small amount of isotropic brown earth. [IIIF multi-mode viewer]
Fig. 51 Vermeer, Girl with the Red Hat, dispersed pigment sample of greenish shadow from the face that includes yellow earth and isotropic brown earth with large, deep blue-green particles of green earth (white arrow) (photographed with slightly uncrossed polars). The sample also includes minor amounts of minor amounts of white lead, vermilion, and traces of black and red lake. [IIIF multi-mode viewer]
Fig. 52 Vermeer, Girl with a Flute, dispersed pigment sample of greenish shadow from the face, with small, pale pigment particles of green earth (white arrows) and a substantial proportion of large, glassy particles (black arrows) (photographed with slightly uncrossed polars). The sample also includes yellow earth, brown earth, a minor amount of black, and traces of white lead and vermilion. [IIIF multi-mode viewer]

Footnotes

  1. 1. Two hyperspectral reflectance imaging instruments were used, one sensitive from 400 to 950 nm (2.5 nm spectral sampling) and the other from 1000 to 2450 nm (2.8 nm sampling). In each case, the spatial sampling at the paintings was 0.2 mm per pixel. The analysis of the RIS image cubes was done using ENVI (L3 Harris) after mosaicking and image registration to a reference color image using in-house software tools.

  2. 2. Multispectral infrared reflectance images were collected with a custom infrared camera consisting of a cooled infrared detector array (indium antimonide, 1280 x 1024 detectors, IRCameras), a custom infrared lens (Stingray Optics), and one of three possible spectral filters (1100 to 1400 nm, 1500 to 1800 nm, or 2100 to 2450 nm). The spatial sampling at the painting was 0.045 mm per pixel. The resulting images were mosaicked and registered to a reference color image using in-house software tools.

  3. 3. A custom XRF instrument was used consisting of a rhodium source with a converging capillary optic (XOS) operated at 50kV and 0.75 mA. The resulting X-ray emission was measured using a silicon drift detector (XG-Labs) with an effective detector area of 50mm2 and a digital pulse processor. The collection conditions were a 0.25 mm spot size at the painting, a pixel dwell time of 0.05 sec, and a scan speed of 5 mm per second. Image registration of the XRF image cube to a reference color image was done using in-house software tools. The chemical element maps were generated by fitting the registered XRF image cube using Pymca software (European Synchrotron Radiation Facility).

  4. 4. Paint cross section samples were mounted in polyester resin and then ground and polished to expose the layers. Mounted samples were examined using a Leica DMRX research microscope with incident illumination using both visible light and autofluorescence at magnifications up to 500x.

  5. 5. Uncoated samples were examined using a Hitachi S-3400N scanning electron microscope with tungsten filament operating at 20 kV in variable pressure mode at 30 to 40 Pa at a distance of 10 mm from sample to detector. Elemental data was acquired using an Oxford Instruments 80mm2 SSD detector and Aztec 300 spectrometer and software package. Elemental data was corroborated by visual characteristics observed in the cross section.

  6. 6. Dispersed pigment samples were mounted in Cargille Meltmount (n=1.66) for microscopic examination in transmitted light. Mounted slides were examined using a Leica DMRX polarizing light research microscope at up to 500x magnification.

Bibliography

Imprint

Author: E. Melanie Gifford, Kathryn A. Dooley, John K. Delaney
Publication Date: Summer 2022
Review: Peer Review (Double Blind)
DOI: 10.5092/jhna.2022.14.2.4
License:
Creative Commons License
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
Recommended Citation:
E. Melanie Gifford, Kathryn A. Dooley, John K. Delaney, "Methodology & Resources: New Findings from the National Gallery of Art," Journal of Historians of Netherlandish Art 14:2 (Summer 2022) DOI: 10.5092/jhna.2022.14.2.4
Keywords:
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