Digital Humanities Workshop: Computational Photography Techniques for Artworks and Historical Artifacts

Through lectures, demonstrations, and discussion, this workshop provides a condensed overview of computational photography and its application to cultural heritage. Computational Photography extracts and synthesizes information from image sequences to create a new image containing information not found in any single image in the sequence. This workshop offers an intensive introduction to the technologies, software, photographic equipment, and methods for reflectance transformation imaging (RTI), and 3D photogrammetry. These techniques are widely applied to a variety of art objects and other examples of material culture.

RTI creates scientific digital representations of an imaging subject’s shape and color. These digital representations are generated from image sequences where the light illuminating the photo’s subject is moved to a new location for each photograph. The lighting information from this image sequence is mathematically synthesized into an RTI image. The subject’s shape and color can be examined in an RTI by interactively re-lighting the subject from any direction and applying mathematical enhancements within an RTI software-viewing environment.

RTI is used on a wide range of subjects, including inscriptions, rock art, manuscripts, engravings and paintings. The workshop will show examples from museums and historic sites. It also provides an overview of the free RTI software.

Photogrammetry refers to the practice of deriving 3D measurements from photographs. It can be used for documenting 3D subjects, monitoring changes to these subjects over time, and a wide range of other uses. Photogrammetry, when done correctly, creates accurate and measurable 3D models on a wide range of scales. Recent technological advances in digital cameras, computer processors, and computational techniques, such as sub-pixel image matching, make photogrammetry a portable and powerful technique. It yields extremely dense and accurate 3D surface data. It can be generated using a sequence of photos and captured with standard digital photography equipment, in a relatively short period of time.