Encaustic: Hot Wax Painting From Ancient Egypt to Modern Art

The faces stare out from wooden panels with an immediacy that is startling after 2,000 years. A young man with a beard, his eyes large and dark, his skin rendered in soft, blended tones that look more alive than anything else surviving from the ancient world. These are the Fayum mummy portraits, painted in the 1st to 3rd centuries CE by artists working in Roman Egypt, and they are the finest surviving examples of encaustic painting. The medium, hot beeswax mixed with pigment, has preserved these faces with a clarity that makes them look like they could have been painted yesterday. The wax has not yellowed, cracked, or faded. It is chemically stable in a way that oil paint, invented over a thousand years later, still is not.

Encaustic is a painting technique in which pigment is mixed with molten beeswax and applied to a surface while hot. The word comes from the Greek "enkaustikos," meaning "to burn in," which refers to the final step of the process: after the pigmented wax is applied, a heat source is passed over the surface to fuse the individual brushstrokes or knife marks into a uniform film. This "burning in" is what distinguishes true encaustic from other wax-based techniques. The wax does not dry by evaporation or oxidation. It solidifies by cooling, and it can be remelted and reworked at any point.

This entry covers how encaustic works, its history from ancient Greece and Egypt to 20th-century revival, the debate over how the ancients actually used it, and the artists who have worked in this most unusual of painting mediums.

What Is Encaustic and How Does It Work?

The basic ingredients of encaustic paint are beeswax, pigment, and sometimes resin. The beeswax is melted, typically at around 150 to 180 degrees Fahrenheit (65 to 82 degrees Celsius), and pigment is mixed into the molten wax. The paint is applied with heated brushes or metal tools to a rigid support, usually wood. Because the wax begins to cool and harden the moment it leaves the heated tool, the painter must work quickly. Each stroke sets almost instantly, and the surface can be built up through successive layers of fused wax.

The final step, the "burning in," involves passing a heat source over the entire surface to remelt and fuse all the layers together. In antiquity, this was done with a bronze tool called a cauterium, heated over a brazier. Modern encaustic painters use heat guns, torches, or heated palettes. This fusing step is what makes encaustic a single, integrated surface rather than a series of separate wax layers. Without it, the layers would remain distinct and could delaminate.

The properties of beeswax as a paint medium are distinctive. Wax is chemically inert, meaning it does not react with pigments the way oil binders do. It does not yellow. It does not crack with age in the way that oil paint does, because wax remains flexible at room temperature. It is impervious to moisture, which is why the Fayum portraits survived in the damp conditions of Egyptian tombs. And it can be remelted and reworked at any time, even centuries later, which gives encaustic a unique relationship to time: the painting is never truly "finished" in the chemical sense that an oil painting is, because the wax can always be remelted.

However, encaustic is vulnerable to heat. A painting left in a hot car or near a radiator can soften or melt. This practical limitation is one reason the medium has never been widely adopted. It requires a heated studio, careful handling, and a willingness to work with materials that can burn.

The Ancient Debate: Hot Wax or Cold Emulsion?

How exactly the ancient painters used encaustic has been debated for centuries. The ancient sources, particularly Pliny the Elder's Natural History (1st century CE), describe the technique but provide few technical details. Pliny mentions "Punic wax," a processed form of beeswax, but does not explain how it was prepared or used. Two main theories have dominated the debate: a "hot" technique in which pure beeswax is applied molten, and a "cold" technique in which the wax is saponified (treated with alkali to create a soap-wax emulsion) and applied at room temperature.

The cold emulsion theory has gained support because chemical analyses of ancient encaustic paintings consistently find fatty acid soaps alongside beeswax, which would be expected if the wax had been saponified. A study published in Analytical Methods by researchers at Cooper Union characterized the binding medium in Roman encaustic paintings and found evidence of beeswax and soap in samples from Roman-Egyptian mummy portraits and Roman wall paintings. The researchers demonstrated that a wax-and-soap technique could reproduce the physical characteristics of the ancient portraits more accurately than hot wax encaustic. Read the study at Cooper Union.

A 2018 study in Microchemical Journal, conducted within the EU consortium IPERION-CH, took a multi-analytical approach to experimentally prepared encaustic paints, comparing hot and cold techniques before and after aging. The study showed how differences in production technology alter the properties and composition of the medium, and how aging can mimic or conceal the evidence for wax processing. Read the study at ScienceDirect.

A more recent study by researchers at the Metropolitan Museum of Art, published in Academia, used FTIR, Raman, and pyrolysis-GC/MS to analyze both experimental samples prepared from ancient recipes and archaeological samples from encaustic paintings. The results suggest that the ancient technique may have involved both molten wax and saponified wax, depending on the context and the desired effects. Read the study at Academia.edu.

History and Origins

Encaustic is one of the oldest painting techniques. The earliest references come from ancient Greece. Pliny credits a painter named Pausias, who worked in Sicyon in the 4th century BCE, with developing the technique for large-scale panel painting. The most famous ancient encaustic paintings are the Fayum mummy portraits, produced in Roman Egypt between the 1st and 3rd centuries CE. These portraits were painted on wooden panels or directly on linen shrouds and placed over the face of the mummified body. Approximately 900 Fayum portraits survive in museum collections worldwide, and their state of preservation is remarkable. The colors are fresh, the faces are individualized, and the painting technique shows a level of naturalism that was not seen again in Western art until the Renaissance.

After the Roman period, encaustic fell out of use. The technique was complex, required heated tools, and could not compete with the simplicity of tempera or fresco. By the medieval period, knowledge of how to prepare and apply encaustic was largely lost. The 18th and 19th centuries saw several attempts to reconstruct the ancient technique, motivated by archaeological discoveries and a desire to understand how the Fayum portraits were made. These reconstructions, by artists and chemists, produced varying results and did not lead to widespread adoption.

The 20th century brought encaustic back into fine art practice. The invention of portable electric heating tools made the technique practical for studio use, and several major artists adopted it for its unique surface qualities and archival stability.

Key Artists and Masterworks

The Fayum Portrait Painters (1st-3rd century CE)

The unknown artists of the Fayum portraits are the masters of encaustic. Works like Portrait of a Young Man (c. 130-150 CE, British Museum, London) and Portrait of a Woman (c. 2nd century CE, Metropolitan Museum of Art, New York) show the medium at its finest. The soft blending of skin tones, the individualized features, and the direct gaze of the subjects all demonstrate what molten wax can do as a painting medium. The portraits were painted quickly, while the wax was hot, which means the brushwork has a fluency and confidence that is difficult to achieve in slower-drying mediums.

Jasper Johns (b. 1930)

Johns is the most prominent modern encaustic painter. His Flag (1954-55, Museum of Modern Art, New York) is made with encaustic and collage on canvas. Johns chose encaustic because the fast setting time of the wax allowed him to build up the surface in distinct layers, each one recording a specific moment of decision. The wax surface has a matte, waxy quality that is different from both oil and acrylic, and the layers of newsprint embedded in the wax are visible through the translucent red and white stripes. Johns's use of encaustic was a deliberate choice to work with a medium that had historical depth and that produced a surface no other medium could replicate.

Diego Rivera (1886-1957)

Rivera used encaustic in some of his murals, most notably in the History of Mexico mural (1929-1935, National Palace, Mexico City). The durability of wax made it suitable for a public mural that needed to withstand the Mexican climate, and the medium's ancient pedigree resonated with Rivera's interest in pre-Columbian art and culture.

Fritz Faiss (1907-2000)

Faiss, a German painter associated with the Bauhaus tradition, developed a modern encaustic technique using Punic wax preparations. His research into ancient wax processing methods contributed to the revival of encaustic in the 20th century and influenced later practitioners.

Encaustic Conservation

Encaustic paintings are chemically stable but physically vulnerable to heat and mechanical damage. A 2025 study from Chalmers University of Technology developed cellulose nanocrystal-stabilized beeswax dispersions for consolidating encaustic paintings, addressing the problem that commercial adhesives are often incompatible with the original wax. The beeswax-based formulations, containing only green components and free of volatile organic compounds, achieved better performance than commercial consolidants on encaustic mock-ups. Read the study at Chalmers Research.

See Encaustic in Person

The best place to see ancient encaustic is the Fayum portrait collection at the Metropolitan Museum of Art in New York, which has one of the finest holdings outside Egypt. The British Museum in London and the Petrie Museum at University College London also have significant collections. For modern encaustic, Jasper Johns's Flag at MoMA is the essential work.

When you look at a Fayum portrait, consider that the face you are seeing was painted by an artist who dipped a brush in molten wax and worked quickly before the wax cooled. The medium has not changed in 2,000 years. The wax has not faded. The pigments have not darkened. This is what makes encaustic unique among painting mediums: it does not age. For more on other ancient and traditional painting mediums, read our entries on tempera, fresco, and oil painting, or explore our blog post on how to read a painting.