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Students use new technology to document ancient carvings

Olivia Snover '19 and Claire Mumford '18 at the Jeffers Petroglyphs.
Olivia Snover ’19 (left) and Claire Mumford ’18 at the Jeffers Petroglyphs, a North American indigenous rock-art site located in southwestern Minnesota.

Two St. Olaf College students are preserving a 7,000 year old story told by ancient rock carvings at Jeffers Petroglyphs.

Claire Mumford ’18 and Olivia Snover ’19, with the guidance of St. Olaf Professor of History Tim Howe, have spent the summer in Comfrey, Minnesota, using Reflectance Transformation Imaging (RTI)  to record half a mile of Dakota religious carvings.

“RTI is a type of computational photography that captures images that you might not necessarily be able to see with the naked eye,” Mumford says. “We have a fixed camera pointing down at the petroglyphs and then we move a mobile light source around the petroglyph to capture how the light picks up surface detail from every angle. Using this method, we take about 55 photographs per petroglyph.”

Olivia Snover '19 and Professor of History Tim Howe work set up the Reflectance Transformation Imaging (RTI) equipment.
Olivia Snover ’19 and Professor of History Tim Howe work set up the Reflectance Transformation Imaging (RTI) equipment at the Jeffers Petroglyphs.

These photos are later processed through RTI Builder and RTI Viewer to allow an image of each petroglyphs to be viewed on a computer from every angle and with different lighting options.

“Jeffers Petroglyphs is a spiritual site for the Dakota people,” Snover says. “A lot of the petroglyphs represent something more. For example, there are a lot of buffalo carvings and often times they represent vitality and life as they are are historically a sacred animal to the Dakota people.”

Mumford and Snover are completing this work as part of the St. Olaf Collaborative Undergraduate Research and Inquiry (CURI) program.

A photograph of the Jeffers Petroglyphs.
A photograph that Claire Mumford ’18 and Olivia Snover ’19 took while working at the Jeffers Petroglyphs.

The St. Olaf CURI program provides opportunities for St. Olaf students from all academic disciplines to gain an in-depth understanding of a particular subject by working closely with a St. Olaf faculty member in a research framework.

“With our CURI project we are looking at Dakota myths and comparing how those myths have changed throughout the years according to political climates and changing ideas,” Mumford says.

Mumford and Snover will continue their work this fall, when they will collaborate with computer science students at St. Olaf to develop a website for the Historical Society that will allow the petroglyphs to be viewed interactively.

“The idea that we can be working on this project for the next year and it can become something a lot bigger is exciting,” says Mumford. “We can pass down this data to future students and researchers so they can use it, along with the Historical Society.”