Ancient Egyptian pigment provides modern forensics with new coat of paint

Ancient Egyptian pigment provides modern forensics with new coat of paint

(Read the article on one page)

It was during a trip to Indianapolis that Professor Simon Lewis, a forensic and analytical chemist, was approached by Gregory Smith from the Indianapolis Museum of Art (IMA) with an idea.

Smith, senior conservation scientist at the IMA, had read and known of Lewis' search for new luminescent compounds that could be used in fingerprint detection.

It was common practise in Smith’s work to use white light to sweep ancient painted artefacts to find traces of an ancient pigment, which was revealed by viewing in the near infrared part of the spectrum.

Egyptian Blue is considered to be the earliest known artificial pigment with origins dating back to 3200 BCE. Even on artefacts dating back several thousands of years, Egyptian Blue still glowed brightly in the near infrared.

Smith asked if Lewis had considered using artistic pigments in his fingerprint research?

The rest as they say, was history.

Egyptian Blue pigment was found to be  a promising candidate as luminescent fingerprint dusting powder . Under visible light it lit up the fingerprints in the near infrared against non-porous or patterned surfaces, such as polymer notes or soft drink cans, outperforming commercially available fingerprint dusting powders.

The findings could bring new colour not only to the field of modern forensics but also challenges in artefact conservation, demonstrating how the past could provide solutions for the future.

Out of the blue

Egyptian Blue is a pigment with a remarkable lineage that showcased the ancient Egyptians' highly advanced grasp on chemistry.

The colour is a synthetic product,  prepared with a mixture of copper-containing material, sand and a strong alkali . The compound is then roasted to around 800℃ to 900℃ under very tightly controlled conditions.

Ancient Egyptian mask image showing Egyptian blue pigment.

Ancient Egyptian mask image showing Egyptian blue pigment. Indianapolis Museum of Art, Author provided

In ancient Egypt, this vivid blue product was highly favoured and widely used as a pigment in paintings such as tombs and mummies' coffins.

The faience technique used a blue ceramic glaze that contained Egyptian Blue on art objects such as amulets and figurines.

Egyptian blue was widely used by ancient Egyptians as a ceramic glaze known as faience, shown in this hippopotamus figurine.

Egyptian blue was widely used by ancient Egyptians as a ceramic glaze known as faience, shown in this hippopotamus figurine.  Carole Raddato/Wikimedia Commons CC BY-SA

Beyond its brilliant blue colour, the pigment also glowed in near infrared, a characteristic that researchers had their eye on.

“You can use that to detect latent fingermarks on non-porous surfaces,” Professor  Simon Lewis , from the Nanochemistry Research Institute at Curtin University, told The Conversation.

Fingerprint detection is still a critically important part of forensic investigation. To detect a fingermark, a dusting powder is used that that would provide the highest possible contrast to the surface, in order to show the ridge and contour details of the fingerprint.

But in the case of highly patterned, dark or reflective surfaces, this can prove troublesome.

The advantage of Egyptian Blue is that when you shine white light on the pigment, it is able to absorb the energy from the light and then emit it in the near infrared part of the spectrum, which our eyes are unable to see.

Lewis said a similar example could be seen in a gin and tonic, but in the ultraviolet light spectrum.

“Have you ever held up a glass of gin and tonic and seen a blue haze in it?” he said.

“What you are seeing there is the quinine in the tonic water, which is a fluorescent compound. It absorbs the ultraviolet light and then emits it as visible light.”

Latent fingermarks dusted with micronised Egyptian blue.

Latent fingermarks dusted with micronised Egyptian blue. Ben Errington, Author provided

Researchers from Curtin University and conservation scientists from the Indianapolis Museum of Art showed that using Egyptian Blue as a dusting powder consistently provided good contrast compared to commercial powders, with it glowing brightly even on difficult surfaces.

The method of using white light to illuminate the fingerprints was safe, simple and inexpensive. A slightly modified digital camera was used to photograph them, by removing a filter that usually prevents near infrared light from getting to the camera sensor.

The hard grind

Fortunately for Lewis’s team, Egyptian Blue is still being manufactured. Its main users are art restorers and conservation scientists, who still favour using the traditional pigments.

“There are a lot of artists and of course conservation scientists who like to use the older pigments. It’s readily available and can be purchased relatively straightforwardly,” Lewis said.

Comments

The Ancient Egyptian art is amazing! since the early start of ancient Egypt in 3500 B.C. and ancient Egyptians still surprise us every day!

Register to become part of our active community, get updates, receive a monthly newsletter, and enjoy the benefits and rewards of our member point system OR just post your comment below as a Guest.

Related Ancient Origins Articles

Our Mission

At Ancient Origins, we believe that one of the most important fields of knowledge we can pursue as human beings is our beginnings. And while some people may seem content with the story as it stands, our view is that there exists countless mysteries, scientific anomalies and surprising artifacts that have yet to be discovered and explained.

The goal of Ancient Origins is to highlight recent archaeological discoveries, peer-reviewed academic research and evidence, as well as offering alternative viewpoints and explanations of science, archaeology, mythology, religion and history around the globe.

We’re the only Pop Archaeology site combining scientific research with out-of-the-box perspectives.

By bringing together top experts and authors, this archaeology website explores lost civilizations, examines sacred writings, tours ancient places, investigates ancient discoveries and questions mysterious happenings. Our open community is dedicated to digging into the origins of our species on planet earth, and question wherever the discoveries might take us. We seek to retell the story of our beginnings. 

Ancient Image Galleries

View from the Castle Gate (Burgtor). (Public Domain)
Door surrounded by roots of Tetrameles nudiflora in the Khmer temple of Ta Phrom, Angkor temple complex, located today in Cambodia. (CC BY-SA 3.0)
Cable car in the Xihai (West Sea) Grand Canyon (CC BY-SA 4.0)
Next article