( Originally Published 1913 )
ENCAUSTIC, or wax-painting, and the fixing or finishing of the same by the application of heat, was practised by the ancient Greeks and Romans, as one of the methods of painting on panels and on walls. It was also a favourite method of painting employed by the early Christian artists, and was practised, though in diminishing degrees, until the middle of the fourteenth century, and even a little later, when it became obsolete.
From the fact that wax-painting is not mentioned by Cennini in his exhaustive treatise on painting, written in 1437, it would appear that it was not practised in his days, or even for a long time previous to the date of his writing, probably not after Giotto's time.
In the National Gallery, London, there are ten interesting examples of Greek or Greco-Roman encaustic paintings on wood, of the second or third centuries. They consist of life-sized heads, and are portraits taken from mummy cases, discovered by Professor Flinders Petrie in an ancient cemetery in the Fayűm district of Egypt, in 1888. Their freshness of colouring and their good state of preservation are testimonies to the permanent qualities of encaustic, and to the prevalence of this method of painting in the early Christian times. In the notice of Greek and Roman painting in Chapter IV of this volume mention has been made of the use of wax in the general application of colouring to buildings, and in the colours used for the painting of the ornamental polychrome patterns on the Greek temples, as well as being one of the ingredients in the varnish-like medium applied as a tinting coating to statues, columns, etc. This ancient Greek wax-varnish was known as " circumlitio," and was often used in its pure state on statues and columns, when its pale yellowish tint would slightly tone the white marble to a warmer shade, but sometimes it was mixed with colours, as in the " variata circumlitio " mentioned by Seneca, and was then applied as a tinted varnish to walls, columns and statues. The former colourless cerate (wax mixture), according to Vitruvius, was used as a finishing varnish to protect, and also to revive the colouring of paintings and polychrome decorations that had been executed on the walls, cornices, and ceilings of the temples at previous periods.
Among the uses of wax-painting and varnishing as a protective covering of wood and stone surfaces, etc., and in the coarser forms of decoration, the ancient Greeks used wax varnish also for the painting of their ships. Not only did the Greeks paint their ships in order to protect the vessels from the action of the sun and weather, but they also decorated them in polychromy. We have evidence that even some distinguished artists began their career as ship decorators, notably Protogenes and Heraclides, whom Pliny mentions as " painters of ships," and who subsequently became famous as tempera painters. Homer speaks of the painted ships of his time. Pitch, thinned with naphtha, was always employed by all nations, and quite likely in prehistoric times, as a protective coating on ships to preserve the wood from the action of the water, and to make the joining of the timbers watertight, but the Greeks used not only a fine sort of pitch, but also wax dissolved in naptha, which they employed as a vehicle for their colours in ship decoration as they also did in other forms of encaustic painting.
From all accounts we find that the Greeks always sought to obtain a shining or enamelled surface on their walls, and even on their tempera paintings, so the common use of wax in their wall paintings afforded the means of obtaining this desired end, for although the wax colours or varnish would dry with a mat or dull surface, after being first applied on the smooth and finely stuccoed walls, the surface was capable of receiving a very high polish by subsequent frictional rubbing with cloths. Tempera paintings, on the other hand, obtained their glossy surface by the final application of a resinous varnish which did not contain wax. Among the more celebrated names of the old Greek artists who worked exclusively in tempera we find those of Apelles, Zeuxis, and Parrhasius.
Encaustic painting was at first practised by the Greeks in the coarser and also in the purely ornamental forms of painting, as a protective paint or varnish for woodwork and ornamental decoration, but was afterwards elevated by them to the more refined uses in the higher forms of pictorial art and figure painting.
The material, methods, and tools employed by the ancients in the practice of encaustic painting have been described by Pliny and other old writers. Though the term " encaustic " literally means " burning in " or " inustion," the process, however, is not so much of a burning in of the colours and medium, but is more of the application of heat during the progress of the work, as well as after the painting is completed, when heat was again applied in order to fuse the colours more effectively, and so give the required finish to the work. From the nature of the wax colours and the metal tools used in manipulating these colours, the paintings before being finally fused by heat, would present a rough and patchy, or mosaic-like appearance, which could only be removed by the application of a gentle heat and final polishing.
Pliny mentions three kinds of wax or encaustic painting. He says : " Anciently there were two modes of painting in encaustic (one), with wax, and (the other) on ivory by means of the cestrum or graver till ships began to be painted. This (the latter) was the third mode introduced, or one in which the brush was used, the wax colours being dissolved by fire." The explanation of the latter passage is, that the wax colours already prepared were first heated, or dissolved by fire, and then sufficiently diluted by an essential oil or spirit, such as naphtha, in order that they might be rendered thin enough to be spread on with a brush, but that heat was not afterwards applied. We can easily understand that if wax colours, in a warm or heated state, are rendered into a fluid by the addition of a naphtha vehicle, that such mixtures may be spread over surfaces, such as ships or walls, while the mixture is warm, particularly if done in warm weather, and that such surfaces would not require any final application of artificial heat.
The above method of painting can hardly be called encaustic, as no after application of heat is required. It may be compared, if not similar to the modern spirit-fresco system of painting, which is a kind of wax-painting, in which the colours are ground in a medium consisting of wax, gum elemi and copal, dissolved in oil of spike lavender, or turpentine. The only difference between the old and new methods just mentioned appears to be that the colours were rendered fluid in the ancient practice by heat and the naphtha spirit, whereas in the modern method a spirit, like the oil of spike, is sufficient to render them fluid, without the application of any heat.
The first mentioned mode of encaustic painting, by Pliny, was the common, and chief one practised by the Greeks, and may be called modelling, rather than painting in wax. The wax colours were applied with a heated metal instrument, instead of a brush. This instrument, which may have been made in various sizes, was called a " cestrum," or graver ; it was pointed at one end, like a stylus, and was slightly curved and flattened at the other end, so that it could be used as a sort of modelling tool. Another tool used was the " rhabdion," a small metal rod, flat also at one end, and used probably for the smaller encaustic paintings. The " cauterium " was the heat-giving agent, which either took the form of a metal heater, or was a pan of coals or a small charcoal stove. The cauterium was essential for the final inustion or burning in, which completed the perfect fusion of the roughly modelled wax colours, that would otherwise have a mosaic-like appearance due to the imperfect manipulation of them with the cestrum. This kind of encaustic was used in the wood panel pictures and on walls. Small encaustic pictures, painted by Greek artists, were held in great esteem, and were much prized by the rich Roman collectors.
The second ancient mode of encaustic was that of engraving on ivory with a sharp metal tool, and the design presented in shaded linear work, cut into the ivory, like an intaglio. These lines would afterwards be filled in with various wax colours in a heated state, and the panel, or ivory plaque, would be finally covered with a wax varnish and polished. This particular kind of engraving on ivory and filling in the lines after-wards with wax of various colours would remind us of the Italian sgraffito work, or of the methods employed in champlevé enamels, and must have resembled the latter in its general effect. It appears to have been chiefly adopted by the Greeks for miniature encaustic paintings, and for portraits executed on a small scale.
During the later classic, and early Christian periods, encaustic painting with the brush was the common method practised by the Greek and Roman artists, the wax being still assisted to flow by the application of heat, and quite likely also further assisted to this end by the addition of some spirit or essential oil. The wax-painted portraits in the National Gallery have been executed in the method here suggested, as it is evident from their technique that some kind of oil, probably naphtha, has been used as a solvent of the wax colours.
This method was so common in the early Christian times that the term " encaustic " was applied to almost all kinds of painting and illumination work.
Wax was used as one of the ingredients of varnishes from very early times up to the fourteenth century, after which it was rarely if ever used, but in recent times wax-painting, or a partial kind of such, has been practised in Germany, France, and Italy, and lately in England ; but in all of these later instances the wax is dissolved by an essential oil, such as turpentine, naphtha, and oil of spike, and rarely by the application of heat. In the modern method the sole object of using wax as one of the ingredients of the colour mediums or varnishes, has been in order to obtain a dull or mat surface on paintings, and especially on wall decorations, so that the work may have the appearance of a fresco, and not shine like an oil painting. This aimed-for effect is, of course, quite contrary to the ancient practice, where a shiny or enamelled surface was always sought for, and obtained by rubbing and polishing the work when quite dry.