Egyptian Blue:The Color Whose Invention Continues To AdvanceTechnological Progress Today
by Shahinda Abdalla
Egyptian Juglet, ca. 1750–1640 B.C. (Photo: Met Museum, Rogers Fund and Edward S. Harkness Gift, 1922. (CC0 1.0)) (Image Credit)
Egyptian blue, also known as copper silicate, is a pigment that was used in ancient Egypt for thousands of years. Blue was a very important color to the ancients with associations to the sky and the River Nile; it came to represent the universe, creation and fertility. Though it was far easier for the ancients to love the color than to find it. Up until the invention of Egyptian blue, they would resort to making pigments from naturally occurring materials like charcoal, clay, and other materials found from surface soil, so the pigments used were predominantly earthy — all different shades of red, yellow and brown. Blue was rare and expensive, coming from minerals like lapis lazuli and turquoise, and so with such high demands for this stark blue color, a synthetic pigment was born. It is thought to be the first synthetic pigment ever made. Its origins date back to the Fourth Dynasty and was used extensively up until the end of the Roman era, after which its use declined until it eventually disappeared and the way to create it was forgotten. No historical record has been found of how to make this pigment. The only clue there was of its components was by Vitruvius, a Roman writer in the 1st century BC, stating that sand, copper (from a mineral such as azurite or malachite) and natron (a naturally occurring mixture of sodium compounds, including sodium carbonate) were the ingredients. Today, scientists have been able to analyze its chemistry and figure out how to make it again, rediscovering old uses and advancing technologies with new ones.
Temple of Dendera (Image Credit)
It is unknown whether the discovery of Egyptian blue came about by chance or through intentional design. Either way the invention of Egyptian blue was a great accomplishment and one that would have been very challenging as it required specific temperature controls for a successful reaction to occur. Another testament to the skill of the ancient Egyptian chemists is the consistency of the pigment throughout history. The composition of Egyptian blue found in artworks such as the mastabas (or tombs) of Mereruka, from the Old Kingdom (2600-2100 BC) is almost exactly the same as those found in a mummy coffin dating from the Greco-Roman period (330 BC-400C).
Hieroglyphic carvings and paintings on the interior walls of an ancient Egyptian temple in Dendera (Image Credit)
The term for the pigment Egyptian blue in the Egyptian language is ḫsbḏ-ỉrjt, which means artificial lapis lazuli (ḫsbḏ). Lapis lazuli was a mineral that was revered and used widely by the ancients, so its no surprise that when they chose to produce a synthetic material, they would aim for a lapis look-a-like. The theory goes that there was such high demand for the stark blue color of lapis lazuli and turquoise that the creation of a synthetic material was necessary to meet this high demand. The pigment Egyptian blue was used in antiquity to color a variety of materials, from stone to wood to papyrus and plaster. They would add it in the making of beads, statuettes, scarabs and even pots. They used it in paintings, tombs, and to decorate their walls and ceilings. The earliest evidence for the use of Egyptian blue was found by Egyptologist Lorelei H. Corcoran on an alabaster bowl dating back to the late pre-dynastic period around 3250BC. This bowl is now on display at the Museum of Fine Arts, Boston.
Forensic experts use Egyptian blue to detect fingerprints when conventional methods fail. Fingerprints can be difficult to pick out on a shiny or highly patterned surface. (Image Credit)
In 2009, Egyptian blue was discovered to have exceptional luminescence in the near-infrared region. This discovery was exciting for both the science and art. It meant that the pigment could be easily detected in a non-destructive manner simply by illuminating ancient works of art with near-infrared radiation. The luminescence is so strong that the presence of very small amounts of Egyptian blue can be detected even when no blue color is visible to the naked human eye. The British Museum was able to use this technique to provide the first proof that the Elgin Marbles had once been painted, finding the pigment on several sculptures from the Parthenon. This feature has meant that its presence could be detected on objects which appear unpainted to the human eye, allowing traces of it to be identified in paintings produced as late as the 16th century, long after its use was presumed to have died out. Moreover, this luminescence in the near-infrared appears to have benefits in the advancement of technologies in the field of biomedicine (especially bio-imaging), telecommunications, laser technology and security inks. Other benefits are in the design of construction materials that cool rooftops and walls in sunny climates as well as for tinting glass to improve the performance of solar cells and panels. It seems that this magnificent color has superpowers of its own making a comeback not just in the art world but across the world of science and technology too.