For centuries the blue pigment recipe used by the Egyptians had been a mystery. We just solved it

Not all Treasures They are made up of jewels, gold and precious stones. For a long time a group of researchers from Washington State University It is behind of a treasure equally fascinating but much more elusive: the Egyptian bluethe synthetic pigment older which is recorded and that once used the artists of the ancient Egyptian to decorate from alabaster bowls to coffins, ceramics and murals. Despite their enormous popularity and that the Romans continued to use it, their recipe was lost over the centuries.

Until now.

What is Egyptian blue? One of those mysteries that has been intrigued by archaeologists in half the world. Egyptian blue is basically a dye that stands out for two reasons. The first, because it is the synthetic pigment older known to date. It was used thousands of years ago. The second is its bluish tone, which allowed artists to use it as a much more expensive mineral substitute, such as turquoise or lapislázuli.

With everything and although we talk about “Egyptian blue” in general, the pigment was very heterogeneous. Depending on where it would have been manufactured, how it would have worked with the material or quality of its components, the tone could vary between gray, a more or less deep blue and a green off. A factor that influenced the process for example was how quickly cooled the mixture.

How old is it? Quite. We know that Egyptian blue was already used 5,000 years ago. And that at least. In fact The oldest sample Known is a small alabaster bowl made in the 3250 AC The pigment was used in ceramics, sculptures, murals, sarcophagi, pieces that we still keep today and show its bluish hue. It was also applied to different surfaces, such as wood, stone or cardboard, a material similar to Paper Maché.

Did you only use the Egyptians? No. His color liked the artisans so much that the Romans ended up incorporating it into their palette after the conquest of the ancient Egyptian and came to be used during the Renaissance. The Smithsoninan Institute remember that a few years ago it was discovered that at the beginning of the 16th century Rafael used Egyptian blue in the fresco ‘Galatea triumph’a work elaborated for the Villa Farnesina, located in the neighborhood of Constévere, Rome.

Although Rafael’s intention could be to imitate the old Roman technique, the Washington State University (WSU) Precise that during the Renaissance the pigment formula had practically fallen into oblivion. That is what a team of researchers has now wanted to solve led by the American institution and who has worked side by side with the Carnegie Museum of natural history and the Institute of Conservation of the Smithsoninan Museum.

And how have they done it? Based on trial and error. And try again and again until you give in the nail. The team He thoroughly examined Pigment samples and elaborated 12 recipes in which he experienced with different raw materials and elaboration times. The results have been reflected in An article Posted in NPJ Heritage Science in which he details how he worked with mixtures of silicon, copper, calcium and sodium carbonate dioxide. The main ingredient is the cuprov.

To complete the process, the mixed mixture warmed 1,000º Celsius For different times, between one and 11 hours, in an attempt to replicate the temperature with which the ovens of the time work. The resulting samples were also cooled at different speeds to then study their pigments through microscopy and analysis techniques. The results were compared to real pieces of ancient Egypt.

Is it so complicated? Beyond the materials used or the techniques with which they were mixed, the great challenge for archaeologists has been to replicate the exact tones that Egyptian artisans worked. “One of the things we observed was that with small variations in the process very different results were obtained,” John McColy commentsone of the authors of the study and director of the School of Mechanical and Materials Engineering of the WSU. “There were people who made the pigment, he transported it and then used it elsewhere.”

During their study the researchers in fact discovered that to obtain the most bluish hue, only half of the components that generate the blue color were needed. “It doesn’t matter what the rest contains and that surprised us”, Add McCloy. “You can see that each particle contains a lot of elements. It is not uniform, much less.” To such an extent that the WSU acknowledges that one of the conclusions reached by the experts is that the pigment is surprisingly diverse.

Did you achieve your goal? That seems. In A statement Run a few days ago the WSU says that after trying different formulas and examining the results in detail, its team has managed to “recreate” the famous Egyptian blue. The feat is not only the result of curiosity or advance to better understand the art of the ancient Egyptian. WSU herself recalls that in part the renewed interest in the Egyptian pigment responds to more pragmatic reasons.

“In recent years, interest in this pigment has resurfaced due to its optical, magnetic and biological properties, with potential new technological applications,” Point out The institution. “The pigment emits light in the nearby infrared of the electromagnetic spectrum, invisible to the human being, which means that it could be used for purposes such as traces and create anti falsifications.”

Images | Washington State University, Matt Unger, Joshua Franzos and Carnegie Museum of Natural History

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