A colorful wool sock dating back to ancient Egypt has finally given up a few secrets behind its remarkable construction.

Excavated from a rubbish dump outside the ruins of the ancient Egyptian city of Antinopolis, the striped sock is estimated to date back between 300 to 400 and to have at one point likely warmed the left foot of a child. Despite sitting in the British Museum's collection since 1914, researchers were reticent about probing the artifact further for fear of damaging the fragile object.

"Previously, you would have to take a small piece of the material, from different areas," Dr. Joanne Dyer, a scientist in the museum’s department of scientific research, told the Guardian. "And this sock is from 300 A.D. It's tiny, it's fragile, and you would have to physically destroy part of this object."

The child's sock, as imaged in different wavelengths, was made using color combinations from three plant-based dyes. The child's sock, as imaged in different wavelengths, was made using color combinations from three plant-based dyes. (Photo: PLOS One)

Determined to know more about colorful properties of ancient textiles, Dyer led a team of scientists in developing a non-invasive approach that leverages a technology called multispectral imaging.

In a paper published in the journal PLOS One, the researchers explain how they used a modified Canon 40D camera to analyze the various wavelengths of the sock's colors and determine their source. They discovered that the sock contained no less than seven hues of wool yarn sourced from three plant-based dyes –– madder roots for red, woad leaves for blue and weld flowers for yellow. Some of the yarn was even dyed multiple times to allow for certain colors to stand out.

"It was exciting to find that the different colored stripes found on the child's sock were created using a combination of just three natural dyes," added Dyer.

The team believes this new, non-invasive technique could be applied to countless other fragile textiles to unravel more about their hidden past. Knowing the source of the color, they add, could also prove beneficial for museums wishing to safely display such textiles, as certain natural dyes respond differently to environmental factors.

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

How scientists unraveled the mystery behind a 1,700-year-old striped sock
A colorful wool sock dating back to Ancient Egypt has finally given up a few secrets behind its remarkable construction and beauty.