What Is Multispectral Imaging And How Is It Changing Archaeology And Digital Humanities Today? By Sarah Bond – Forbes: Nov 30, 2017
What is multispectral imaging and how is the technology changing the face of archaeology, art history and digital humanities today? The non-invasive digital technique is making the past visible in ways we never thought possible.
In the world of archaeology and art history, even objects that have long been known to the world are now providing new information for researchers. This is in part due to an approach called multispectral imaging (MSI). Multispectral imaging first began as bulky and expensive remote sensing equipment used by high-tech astronomy labs like those at NASA interested in planetary science and mapping mineral deposits.
Improvements to sensors and apertures have downsized MSI technology and made it more cost-efficient in recent years. Consequently, the technique has become a more regularized part of the fields of digital archaeology and art preservation as a novel means of revealing hidden materials, pigments and inks that the naked eye alone cannot decipher.
The approach detects electromagnetic infrared radiation wavelengths and melds between three and five spectral imaging bands into one optical system. As Haida Liang, a professor at Nottingham Trent University and the Head of the Imaging & Sensing for Archaeology, Art History & Conservation (ISAAC) research group has noted, MSI can take three visible images in blue, green and red and can combine them with an infrared image and an X-ray image of an object in order to reveal minute hints of pigment. It can even reveal hidden drawings, stains or writings underneath various layers of paint or grime.
In a new paper studying a Hebrew ostracon from 600 BCE, the promise of MSI is exemplified. In antiquity, ceramic pot sherds were often used as a kind of scrap paper; however, the ink used on these ceramics can often fade, blur and become illegible. Professors at Tel-Aviv University led by mathematician and imaging specialist Shira Faigenbaum-Golovin used MSI on a number of ostraca predominantly from the southern Beer Sheba Valley and Jerusalem. Most dated to the time of the Kingdom of Judah (ca. 600 BCE) and one in particular revealed an amusing if familiar request of the writer: “If there is any wine, send [quantity].”
As the Tel-Aviv University researchers noted, MSI holds the potential to help us reconstruct the past in new ways: “These examples demonstrate that at least some of the ostraca have ink traces invisible to the naked eye that are detectable by MS photography. They also indicate that in certain cases MS imaging can provide good results even decades after excavation despite overall ink deterioration.”