Christ in the House of Mary and Martha Johannes Vermeer c L02; accession number NG 1670 National Gallery of Scotland

Transcription

1 1 WEAVE MAP REPORT Christ in the House of Mary and Martha Johannes Vermeer c L02; accession number NG 1670 National Gallery of Scotland C. Richard Johnson, Jr. Cornell University 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 Christ in the House of Mary and Martha (L02) 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. comments on observed cusping and weft snakes Observations: The average thread density of Christ in the House of Mary and Martha (H x V) is x th/cm. Christ in the House of Mary and Martha has cusping of depth greater than 5 cm on all four sides. Christ in the House of Mary and Martha has no close count matches, and therefore no weave matches, among Vermeer s other paintings on canvas. The thread angle maps of Christ in the House of Mary and Martha in Figures 7 and 8 display no 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: Close examination of the x-radiograph of L02 at sufficient resolution reveals a vertical seam about one-third of the way across the painting from its right edge. This seam is most clearly revealed in the horizontal thread angle map in Figure 5 as a vertical line separating the weave maps of two connected pieces of fabric with non-aligned stripes. Average Thread Count: For L02 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 ±1.9 th/cm (H) and ±1.76 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, L02 has none. Weave Matches: With no close count matches, L02 has no weave matches anong Vermeer s paintings on canvas. Weft Snake Indicators: No weft snake indicators appear in the thread angle maps of L02. Cusping: The cusping is greater than 5cm in depth on all four sides of L02.

6 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).

7 Johnson and Sethares, Weave Map Report, August Images Figure 1: Christ in the House of Mary and Martha (L02) Note: All of the following images (Figures 2-8) are available on request as high resolution tiff or pdf files.

8 Johnson and Sethares, Weave Map Report, August Figure 2: X-Radiograph of L02

9 Johnson and Sethares, Weave Map Report, August 2017 horizontal thread density ( /- 1.9 threads/cm) vertical thread density ( / threads/cm) horizontal thread angles (+/ degrees) vertical thread angles (+/ degrees) Figure 3: Weave Maps of L02 9

10 Johnson and Sethares, Weave Map Report, August Figure 4: Histograms of Thread Count and Angle Computations for L02

11 Johnson and Sethares, Weave Map Report, August Figure 5: Horizontal Thread Density Map of L02

12 Johnson and Sethares, Weave Map Report, August Figure 6: Vertical Thread Density Map of L02

13 Johnson and Sethares, Weave Map Report, August Figure 7: Horizontal Thread Angle Map of L02

14 Johnson and Sethares, Weave Map Report, August Figure 8: Vertical Thread Angle Map of L02