In the distant past, fresco painting was ideal for brightening up the walls or ceiling of a substantial building, but there was also demand for smaller, more portable works of art. Some would have been painted onto animal skins, and were ultimately developed into miniatures in beautiful manuscripts, using the precursors of watercolours. One alternative medium developed most successfully was wax, in encaustic painting.

Characteristically this uses binder that in most ambient temperatures is solid, but becomes liquid paint at higher temperatures, usually no higher than the boiling point of water. This enables the painter to heat mixtures of pigment and binder kept at around 50˚-90˚C (120˚-200˚F), apply them while still hot, and for them to bind the pigment to its ground once the paint cools.

People started to keep bees by around 7000 BCE, and one of their most important products has been the wax from which they build their hives. Beeswax has a typical melting point of about 63˚C (145˚F), a temperature readily achieved by heating water but well above daytime maximum air temperatures experienced where people live, which very seldom reach 50˚C (120˚F). Beeswax was therefore most probably the first binder used for encaustic painting.

Encaustic paint is thus unusual as it doesn’t rely on a chemical process to form the dry paint layer, but a physical change of state, which is fully reversible. Common supports include panels of wood, which originally didn’t have any ground applied. More recently grounds of gesso have been used successfully, but encaustic paints have also been applied to a wide range of supports including dried and fired clay tablets, pots, and sculpture.

One significant limitation with the process of painting using encaustic media is that heated paint tends to be thin and runny. Most artists therefore apply their paint with the support laid flat, and leave their work horizontal until the paint has solidified. Instead of painting stood up in front of an easel, they tend to work lying down.

Although encaustic paintings are susceptible to physical damage and decay, some from before the Christian era have survived, and it’s thought that the medium was used for several hundred or even thousands of years before the birth of Christ. The best-known early encaustic paintings are those made by colonists from Greece and Rome when living in Egypt between about 80-250 CE, particularly those found in the Fayum (or Faiyum) Basin. These were first discovered in about 1615, with most being removed during the nineteenth century and spread across collections in Europe and America. These funerary portraits are among the most haunting images in European art, and demonstrate how skilled encaustic painting can rival other media. It can achieve a remarkable lucency, although this depends on the processing of the beeswax and its ageing.

This Funerary Portrait of a Woman ‘Isidora’ is rendered in fine, close-packed strokes of encaustic wax to model the form, and the eyelashes have been formed by scraping away wax to reveal the underlying black ground. Originally painted on a rectangular cedar board, small squares of gold leaf were applied around her neck, and the board cut down to size to fit the facial area of the woman’s mummy for interment.

Modelling of the skin in this Funerary Portrait of the Boy Eutyches is well in advance of its time, and appears more characteristic of portraits from the Renaissance over a thousand years later.

A tradition of encaustic painting also grew up in early Christian communities, where it was used to create icons for places of worship and the homes of the wealthiest.

This encaustic painting of the Virgin Mary and Child with Saints Theodor of Amasea and George, and Angels was made in about 580 CE for Saint Catherine’s Monastery in Sinai, not far from where the Fayum portraits had been interred.

A few artists continued to paint in encaustic even after the Renaissance, although this has remained a minority pursuit. Giovanni Francesco Romanelli’s painting of Boys Fishing from about 1640 curiously uses cardboard as its support, suggesting it may have been more of an experiment.

The nineteenth century saw a resurgence in the use of more traditional media such as egg tempera. In addition to painting with that, some like Arnold Böcklin returned to try encaustics, here in one of his major works, the first version of Villa by the Sea from 1864.

More followed suit in the twentieth century, including James Ensor, Diego Rivera and Jasper Johns, and today encaustic methods have a small but enthusiastic following.