Young Woman with a Wine Glass Johannes Vermeer c L10; inv. 316 Herzog Anton Ulrich Museum

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1 1 WEAVE MAP REPORT Young Woman with a Wine Glass Johannes Vermeer c L10; inv. 316 Herzog Anton Ulrich Museum C. Richard Johnson, Jr. Cornell University johnson@ece.cornell.edu William A. Sethares University of Wisconsin - Madison sethares@gmail.com August 2017 In this report, paintings by Vermeer are referred to by L-numbers, based on their numbering in W. Liedtke, Vermeer: The Complete Paintings, Ludion, The dates cited on this cover page span the range of dates estimated in the oeuvre catalogs by Wheelock (1997), Liedtke (2008), and Franits (2015) as compiled in the table at references/dates.html.

2 Johnson and Sethares, Weave Map Report, August Summary This document applies spectral-based, automated thread counting to Young Woman with a Wine Glass (L10) by Johannes Vermeer and includes the following: 1. stitched x-radiograph of full painting 2. vertical thread density map 3. horizontal thread density map 4. vertical thread angle map 5. horizontal thread angle map 6. histograms of vertical and horizontal thread counts and angle maps 7. a listing of all close count matches (within ±1 th/cm in both directions for an H to H and V to V match or an H to V and V to H match) among Vermeer s 34 paintings on canvas 8. a composite image containing thread density maps of the painting being studied and its close count matches to the same scale and colorbar for weave match hunting 9. comments on observed cusping and weft snakes Observations: The average thread density of Young Woman with a Wine Glass is (H x V) is x th/cm. Young Woman with a Wine Glass has cusping of depth greater than 5 cm on all four sides. Young Woman with a Wine Glass has nine close count matches, but no apparent weave matches, among Vermeer s other paintings on canvas. The horizontal thread angle map of Young Woman with a Wine Glass displays three weft snake indicators.

3 Johnson and Sethares, Weave Map Report, August Background Manual thread counting has been used for several decades. One canvas descriptor that has been routinely collected is the average thread count of the threads in each direction (vertical and horizontal) in a painting s canvas. This information has been used to discount the possibility of two canvases coming from the same original roll if their average thread counts (horizontal compared to horizontal and vertical compared to vertical or horizontal compared to vertical and vertical to horizontal) are too different, e.g. by more than 1 th/cm. In 2009, the first weave maps derived from automated thread counts based on a spectral analysis of the painting s x-radiograph were shown at the annual AIC meeting in Los Angeles. The stripes that arise in color-coded images of thread count in small evaluation squares covering the entire painting were immediately recognized as a fingerprint of a specific roll. The first weave match was also shown in this talk [1]. The utility of automated thread counting for canvases with a sufficiently regular weave was confirmed in [2]. Weave matches with art historical implications have been reported for paintings by van Gogh [3], Velázquez [4], and Vermeer [5] [6]. Spectral-based automated thread counting also provides angle maps that make cusping assessment [7] and weft snake hunting [8] easier. Descriptions of the revelations possible from these new visualizations of canvas weave density and thread angle are provided in [9]. Technical description appears in [10] of the algorithms used in composing and comparing weave maps. References [1] C. R. Johnson, Jr., E. Hendriks, P. Noble, and M. Franken, Advances in Computer-Assisted Canvas Examination: Thread Counting Algorithms, 37th Annual Meeting of American Institute for Conservation of Historic and Artistic Works, Los Angeles, CA, May [2] C. R. Johnson, Jr., D. H. Johnson, N. Hamashima, H. S. Yang, and E. Hendriks, On the Utility of Spectral-Maximum-Based Automated Thread Counting from X-Rays of Paintings on Canvas, Studies in Conservation, vol. 56, pp , 2011.

4 Johnson and Sethares, Weave Map Report, August [3] L. van Tilborgh, T. Meedendorp, E. Hendriks, D. H. Johnson, C. R. Johnson, Jr., and R. G. Erdmann, Weave Matching and Dating of Van Gogh s Paintings: An Interdisciplinary Approach, The Burlington Magazine, vol. CLIV, pp , February [4] Pablo Pérez D Ors, C. R. Johnson, Jr., and D. H. Johnson, Velázquez in Fraga: a New Hypothesis about the Portraits of El Primo and Philip IV, The Burlington Magazine, vol. CLIV, pp , September [5] W. Liedtke, C. R. Johnson, Jr., and D. H. Johnson, Canvas Matches in Vermeer: A Case Study in the Computer Analysis of Fabric Supports, Metropolitan Museum Journal, vol. 47, pp , [6] C. R. Johnson, Jr. and W. A. Sethares, Canvas Weave Match Supports Designation of Vermeer s Geographer and Astronomer as a Pendant Pair, Journal of Historians of Netherlandish Art, vol. 9, issue 1, Winter DOI: /jhna [7] P. Noble, A. van Loon, C. R. Johnson, Jr., and D. H. Johnson, Technical Investigation of Rembrandt and/or Studio of Saul and David c from the Collection of the Mauritshuis, ICOM-CC 2011 Lisbon Triennial Conference, Lisbon, Portugal, September [8] C. R. Johnson, Jr., D. H. Johnson, I. Verslype, R. Lugtigheid, and R. G. Erdmann, Detecting Weft Snakes, Art Matters, vol. 5, pp , [9] D. H. Johnson, E. Hendriks, and C. R. Johnson, Jr., Interpreting Canvas Weave Matches, Art Matters, vol. 5, pp , [10] D. H. Johnson, C. R. Johnson, Jr., and R. G. Erdmann, Weave Analysis of Paintings on Canvas from Radiographs, Signal Processing (Special Issue on Image Processing for Art Investigation), vol. 93, pp , March Note: All of these references are available for download from

5 Johnson and Sethares, Weave Map Report, August Observations X-Radiograph: The impression of the canvas is readily visible throughout the x-radiograph of L10 in Figure 2. The absence of strainer bars in the full-painting x-radiograph indicates that the x-ray films were positioned between the canvas and the strainer and that the x-radiograph is unlikely to reach to the edge of the canvas. Average Thread Count: For L10 the average thread count (H x V) is x th/cm. These values are noted at the top of the images in the top row of Figure 3 along with the standard deviations of ±1.41 th/cm (H) and ±1.35 th/cm (V). The thread counts were computed in evaluation squares 0.5 cm on a side centered on a grid of points with 0.25 cm horizontal and vertical spacings. The histograms of the thread counts in each thread direction in the evaluation squares, as well as the histograms of the thread angles computed in the same evaluation squares, are plotted in Figure 4. Tight Count Matches: All of the weave matches discovered so far among the canvases in paintings by Vermeer have had both thread counts within 1 th/cm of each other. Using this metric for the designation of a tight count match, L09 has nine: L06 (Officer and Laughing Girl, Frick Collection), L07 (The Milkmaid, Rijksmuseum), L09 (Girl Interrupted at Her Music, Frick Collection), L11 (The Little Street, Rijksmuseum), L13 (Young Woman with a Water Pitcher, Metropolitan Museum of Art), L16 (The Concert, Isabella Stewart Gardner Museum), L17 (Woman Reading a Letter, Rijksmuseum), L22 (Girl with a Pearl Earring, Mauritshuis), and L23 (Study of a Young Woman, Metropolitan Museum of Art) Weave Matches: Figure 9 is designed to assist in assessing if any of the nine tight count matches is a weave match to L10. In Figure 9 all images are to the same scale, which is necessary for visual evaluation of potentially matching stripe patterns. The first two images in the second row are the horizontal thread density map of L06 and the vertical thread density map of L06 - rotated 90 degrees so the stripes are horizontal - with the same colorbar as used for the horizontal thread count for L10 on the left in the top row of Figure 9. These are to be placed on either the right or the left of the left image in the top row and moved up and down looking for a match of the stripe patterns. The images from the

6 Johnson and Sethares, Weave Map Report, August second row should be rotated 180 degrees as well in seeking matches in the striped patterns. No alignment offering a match of the striped patterns is apparent. A similar visual check is made with the third and fourth images in the second row of Figure 9 against the right image in the top row. The last two images in the second row are the vertical thread density map of L06 and the horizontal thread density map of L06 - rotated 90 degrees so the stripes are vertical - with the same colorbar as used for the vertical thread count for L10 on the right in the top row of Figure 9. These are to be placed either above or below the right image in the top row and moved right and left looking for a match of the vertical stripe patterns. Also, 180 degree rotations of the two rightmost images in the second row should also be considered for matching stripe patterns. No alignment offering a match of the striped patterns is apparent. Of these four images in the second row, only one (or none) can have a match with the corresponding images in the top row. This examination is repeated for the remaining rows containing the weave maps to be compared for all of the other tight count matches to L10. Again, no alignment offering a match of the striped patterns is apparent. Consequently, there appear to be no weave matches for L10 among Vermeer s paintings on canvas with a close count match to L10. Weft Snake Indicators: The horizontal thread angle map for L10 in Figure 7 includes three faint weft snake indicators between about one third of the painting s height down from the top edge to the middle of the painting. A correponding wiggle bundle of horizontal threads can be seen in a close-up of sufficient resolution of the stitched x-radiograph crossing the painting through the white fur collar of the coat worn by the bent over gentleman holding the lady s hand and trying to get her attention. This painting retains its selvedge along its right and left edges. Thus, both the direction of the vertical selvedge and the presence of a horizontal weft snake affirm that the horizontal threads are the weft threads. Cusping: From the thread angle maps of L10 cusping can be observed as greater than 5cm in depth on all four sides.

7 Johnson and Sethares, Weave Map Report, August Acknowledgments The authors of this weave map report on one of Vermeer s paintings on canvas are grateful to the owners of Vermeer s paintings, all of whom gave us access to high resolution digitized x-radiographs of their Vermeers Walter Liedtke (Metropolitan Museum of Art) and Gregor Weber (Rijksmuseum) for their help in persuading the owners of paintings by Vermeer to grant us access to their x-radiographs Rob Erdmann (Rijksmuseum) for expertly assembling full-painting composite x-radiographs all of our research collaborators and thread-counting students over the past decade since the founding of TCAP: the Thread Count Automation Project ( tcap.html).

8 Johnson and Sethares, Weave Map Report, August Images Figure 1: Young Woman with a Wine Glass (L10) Note: All of the following images (Figures 2-9) are available on request as high resolution tiff or pdf files.

9 Johnson and Sethares, Weave Map Report, August Figure 2: X-Radiograph of L10

10 Johnson and Sethares, Weave Map Report, August horizontal thread density ( / threads/cm) vertical thread density ( / threads/cm) horizontal thread angles (+/ degrees) vertical thread angles (+/ degrees) Figure 3: Weave Maps of L10

11 Johnson and Sethares, Weave Map Report, August Figure 4: Histograms of Thread Count and Angle Computations for L10

12 Johnson and Sethares, Weave Map Report, August Figure 5: Horizontal Thread Density Map of L10

13 Johnson and Sethares, Weave Map Report, August Figure 6: Vertical Thread Density Map of L10

14 Johnson and Sethares, Weave Map Report, August Figure 7: Horizontal Thread Angle Map of L10

15 Johnson and Sethares, Weave Map Report, August Figure 8: Vertical Thread Angle Map of L10

16 Johnson and Sethares, Weave Map Report, August Figure 9: Tight Count Matches of L10