Researchers from Washington State University (WSU), in collaboration with colleagues at the Carnegie Museum of Natural History and the Smithsonian's Museum Conservation Institute, successfully recreated 12 authentic variants of Egyptian blue, the oldest synthetic pigment known in human history, according to ARTnews.
Egyptian blue is the oldest known synthetic pigment in the world, first made about 5,000 years ago during the Fourth Dynasty of Ancient Egypt (2613-2494 BCE). The recipe for making Egyptian blue was almost forgotten until the Renaissance.
The research team developed 12 original recipes to make Egyptian blue, identifying different ingredients and cooking temperatures that allow for the preparation of shades of the pigment. They mixed calcium, copper, silica, and sodium carbonate—materials believed to have been obtainable by ancient Egyptian artisans—and heated the mixtures to around 1,000 degrees Celsius for between one and eleven hours, aligning with the capabilities of ancient furnaces.
“We hope this is a good case study of what science can contribute to the study of our past,” said John McCloy, director of the WSU School of Mechanical and Materials Engineering, according to ARTnews. “Only small differences in the process could give very different results,” he added.
The researchers discovered that cooling rates after heating significantly affected the final color. Samples that were cooled slowly, possibly buried in sand or ash to retain warmth, contained up to 70% more cuprorivaite—the blue crystal pigment responsible for the characteristic Egyptian blue—than samples cooled quickly in air. The colors produced from slow cooling were deeper and brighter.
Interestingly, the team found that the desired deep blue color does not have to be obtained solely by using pigments consisting entirely of cuprorivaite. “The color still appears blue even though there are many other materials in it. The pigment particles are not homogeneous, but the final result remains uniform,” McCloy noted.
Egyptian blue encompasses a wide spectrum from intense blue to gray or opaque green, depending on its ingredients and processing time. The pigment was synthesized using mixtures that included twelve types of materials, such as crystalline silica and different sources of copper.
This ancient pigment garnered modern scientific interest due to its properties and potential applications. Egyptian blue emits light in the near-infrared part of the electromagnetic spectrum, which is invisible to humans. This property is now utilized in security inks, biomedical imaging, and telecommunications. Moreover, its chemical composition is similar to that of high-temperature superconductors, opening pathways for new technological explorations in digital security and superconductivity.
The pigment was historically used by ancient Egyptians as a substitute for expensive minerals like lapis lazuli and turquoise. It adorned items including statues, sarcophagi, and murals, and was widely used in funerary rituals. Egyptian blue was valuable in antiquity, allowing for the production of blue-colored objects throughout the Mediterranean region.
The research provides valuable information for archaeologists and conservators studying materials from ancient Egypt, enhancing their work with relics. The team hopes that this pigment can be used in the restoration of ancient objects, with colors that are accurate and faithful to the original.
Recreated samples of Egyptian blue pigment are on display as part of a long-term exhibition about ancient Egypt at the Carnegie Museum of Natural History in Pittsburgh. There are plans for these pigments to become a permanent part of the exhibition in late 2026.
“This was initially just a side project because we were asked to make materials for an exhibition. But it turned out the demand for this pigment is very high,” McCloy remarked.
The preparation of this article relied on a news-analysis system.