More Examples of Reflectance Transformation Imaging
With the widespread growth of interest in RTI, several independent projects that demonstrate its application and efficacy have sprung up around the world. Here are some further examples.
Project: Squeeze Imaging at the Smithsonian
In 2010, a team of specialists funded by the Smithsonian Institution's Collections Care and Preservation Fund used RTI imaging at the Freer Gallery of Art and the Arthur M. Sackler Gallery Archives to study a collection of 393 squeezes from ancient archaeological sites in the Near East. A squeeze is a series of sheets of paper that are layered on top of each other and moistened to create a wet pulp. This substance is pressed upon the inscriptions, creating a paper mold and capturing the impressionistic writing for a 3-dimensional negative effect. Often made of paper that varies in quality, squeezes can be fragile, which limits their accessibility and jeopardizes the historical data they hold. The examples in this collection are from the Ernst Herzfeld Papers and date from 1911–1934. The Archives collaborated with the Smithsonian Institution Museum Conservation Institute (MCI) to create a digital preservation surrogate for each squeeze, using Reflectance Transformation Imaging (RTI).
How to View Interactive Files of the Squeezes (Re viewing, see our note below.)
The Smithsonian's Squeeze Imaging Project has put nearly 400 interactive files on the web in an earlier form of RTI called PTM or “Polynomial Texture Mapping”). See their pages devoted to this area of research:
Note: To view any of the interactive PTM files on the Smithsonian page, click one of the sites listed in the right column (“ARCHAEOLOGICAL SITES”). On the resulting page, click the link under the title to see the actual squeeze images. For more information, read the instructions here: How to View an RTI File.
Video: “Japanese Woodblock Prints and RTI”
The short video embedded below focuses on the results of an RTI project conducted by Cultural Heritage Imaging on a mid-19th-century Japanese woodblock print by Konishi Hirosada. The print, which depicts the Osaka actor Mimasu Daigoro IV, is in the collection of the Fine Arts Museums of San Francisco. Through the application of RTI imaging, the print's embossed and textured surfaces are revealed, enabling a better appreciation of the artist's method and technique and the complexity of the woodcut prints.
Sue Grinols, Director of Photo Services and Imaging for Fine Arts Museums of San Francisco (FAMSF), wrote about the work with CHI in her blog. She and a group of her colleagues have been using RTI to gain better understanding of objects in their permanent collections.
Study: Applying RTI to a 5th-Century BC Greek Pelike
In May 2011, Sue Grinols and her team from Fine Arts Museums of San Francisco (FAMSF) completed a round of RTI photography of this 5th-century Greek pelike. You can read more about this study in Sue Grinols's blog.
Study: Using RTI to Analyze Decorative Techniques on Red Figure Vases
In July 2011, the CHI team conducted a training session at the Worcester Art Museum in Massachusetts with the staff at the conservation lab, as part of our IMLS-sponsored 21st Century Museum Professionals program. Decorative features on a Greek red-figure stamnos in the museum collection were examined using RTI and scanning laser confocal microscopy. These two surface examination tools helped to answer questions relating to the decorative process, particularly the tools and techniques that Attic painters used to create the so-called glossy black “relief lines” and “relief dots”.
You can read more about this study here:
- CHI's 2011 blog about this project, “An Evaluation of Decorative Techniques on a Red-Figure Attic Vase from the Worcester Art Museum”
- CHI's 2014 follow-up blog about this project, “Greek red-figure vases, two surface examination methods and fabricated mock-ups”
- Worcester Art Museum publication (PDF): An Evaluation of Decorative Techniques on a Red-Figure Attic Vase from the Worcester Art Museum Using Reflectance Transformation Imaging (RTI) and Confocal Microscopy With a Special Focus on the “Relief Line”