During the 2009 excavation season, the Tell Atchana team used innovative imaging techniques to document incised objects excavated during the season. This technique uses a group of digital photographs to create, in effect, an ultra high resolution micro-topographic “map” of an artifact or incised surface. Once the digital photographs have been processed, the person viewing it is able to move the light within the image to view the artifact or surface from any light angle. Finally, because the surface of the artifact has been mapped accurately, the program is able to display the artifact in ways not possible with normal photographs, which often allow new details to be perceived.

The technique, referred to as Polynomial Texture Mapping (PTM) [a method of Reflectance Transformation Imaging (RTI)] was created at Hewlett Packard (HP). Members of Inscriptifact and the University of Southern California worked with Cultural Heritage Imaging (CHI) to create user-friendly and field-friendly methods for the technique. This season, members of the field team from USC brought the technique to Alalakh.

In its first season of use, we used the new technique to document both bone and glyptic materials. We photographed each artifact 32 times (each time with a different flash angle). Using software developed by HP, we created an aggregate file. This combined file allows the researcher to move the light source around on the computer screen—in a manner similar to modeling the light across the artifact’s surface when an artifact is held in one’s own hand. The variable light source allows researchers to see details that might otherwise have been difficult to capture clearly in a restricted number of traditional photographs.

Image 1 is a close-up rendering of an RTI image of the cylinder seal impression unearthed at Alalakh during the 2009 excavation season. Notice how the incised topography is especially clear even when zoomed-in.

The end-results are research quality files that can be referenced time and again during the interpretation and documentation phases of research. The technique is convenient because of its portability. The necessary equipment fits in a backpack and works in field conditions. Our bone and glyptic specialists are now working with the newly rendered files, and we look forward to seeing their results.

Image 2 shows an example of the uses of the Inscriptifact Viewer to manipulate the light source of the image. On the left, you see the normal view of the impression. On the right, you see the same image treated with an effect called Specular Enhancement.

During the 2010 study season, we hope to expand the variety of materials photographed. We also hope to expand by training more people in these photography techniques. We will train more members of the Alalakh team and also to continue training the staff at the Hatay Museum where many artifacts from previous excavations at Alalakh are displayed. By training residents in these techniques, we hope to increase the research accessibility of ancient artifacts from Turkey.

For Further Information

Ashley Sands

ashleysa@ucla.edu