RKD Netherland Institute for art History
Beginning with assertions about the similarity of paper sold in the same batch, assumptions about the purchase and use of paper by Rembrandt's studio, and claims about the retention of a sheet of paper's physical dimensions during an existence over hundreds of years including decay and preservation, Rembrandt scholars have devised a strategy for estimating the production date of the various impressions of Rembrandt's prints that relies on matching watermarks and chain line patterns in their antique laid paper supports made in Europe.
The basic premise is that the unique pair of watermarks in a pair of molds used in making European paper in the 17th century was only purchased for Rembrandt's use in one sale and employed in one contiguous time interval. Thus, sheets of paper identified as made on the same pair of twin molds as evidenced by matching watermarks and surrounding chain line patterns should all have the same year (plus or minus one) of creation. This provides a chronology offering valuable insights into Rembrandt's artistic development and production patterns.
This seminar is organized on the occasion of the visit of the RKD Visiting Fellow in Computational Art History, Professor C. Richard Johnson Jr. (Jacobs Technion-Cornell Institute, Cornell Tech, New York City).
C. Richard Johnson, Jr. received the first PhD minor in Art History granted by Stanford University along with a PhD in Electrical Engineering in 1977. Forty years later, he is the Jacobs Fellow in Computational Arts and Humanities at the Jacobs Technion-Cornell Institute at Cornell Tech (New York, NY) and the Geoffrey S. M. Hedrick Senior Professor of Engineering at Cornell University (Ithaca, NY). In the past decade professor Johnson has founded four multidisciplinary, multi-institutional, pioneering projects in the new field of computational art history. Their aim is the development of computer-based procedures assisting in the matching of manufactured patterns in art supports: canvas thread count automation (in 2007), historic photographic paper classification (in 2010), laid paper chain line pattern marking and matching (in 2012), and watermark identification in Rembrandt's etchings (in 2015).
This 2-day seminar offers an introduction to computer-assisted classification of watermarks revealed by radiographic imaging. The course is divided into 4 segments of one and a half hours each. Each segment will include lectures and training exercises.
The technical concept of a decision tree (similar to the parlor game of 20 Questions) is embedded in an interactive interrogatory relying on human responses to a series of Yes/No questions, as described in: A. C. Weislogel, C. R. Johnson, Jr., et al., “Decision Trees and Fruitful Collaborations: The Watermark Identication in Rembrandt's Etchings (WIRE) Project at Cornell" in: Lines of Inquiry: Learning from Rembrandt's Etchings, Ithaca [NY] 2017, pp. 32-57.
The underlying decision tree concept has broad utility in image classification of a variety of maker marks found in the supports of art works, including, for example, panel maker marks and guild brands. This short course will prepare the students to be sophisticated users of this emerging technology and potentially to pioneer its use in other cultural heritage applications.
Wednesday 24 October 13:00-14:30 Session 1: Converting identified watermarks into chronology of Rembrandt’s impressions14:30-15:00 Coffee Break 15:00-16:30 Session 2: Types, variants, sub-variants, and twins
Thursday 25 October 13:00-14:30 Session 3: Scale-invariant features, decision trees, and decision tables14:30-15:00 Coffee Break 15:00-16:30 Session 4: Watermarks in drawings by Rembrandt and his pupils
Friday 26 October 16:00-17:00 RKD Public Lecture: Rembrandt's European Papers: Computer-Assisted Classification of Watermarks and Chainline Patterns for Moldmate Identification17:00-18:00 Drinks