ENCAUSTIC PAINTING. The name encaustic is applied to paintings executed with vehicles in which wax is the chief ingredient. The term was appropriately applied to the ancient methods of painting in wax, because these required heat to effect them. Wax, however, may now be used as a vehicle for painting without heat being requisite ; nevertheless the ancient term encaustic has been retained, and is indiscriminately applied to all methods of painting in wax. The durability of wax, and its power of resisting the effects of the atmosphere, were well known to the Greeks, who used it for the pro-tection of their sculptures. As a vehicle for painting it was commonly employed by them and by the Romans and Egyptians; but in recent times it has met with only a limited application. Of modern encaustic paintings those by Schnorr in the Residenz at Munich are the most impor-tant. At present there is no general agreement as to which is the best method of using wax for mural painting. Modern paintings in wax, in their chromatic range and in their general effect, occupy a middle place between those executed in oil and in fresco. Wax painting is not so easy as oil, but presents fewer technical difficulties than fresco.
Ancient authors often make mention of encaustic, which, if it had been described by the word inurere, to burn in, one might have supposed to have been a species of enamel painting, But the expressions "incausto pmgere," "pictura encaustica, " "ceris pingere, " "pictura inurere," used by Pliny and other ancient writers, make it clear that some other species of painting is meant. Pliny distinguishes three species of encaustic painting. In the first they used a stylus, and painted either on ivory or on polished wood, previously saturated with some certain colour ; the point of the stylus or stigma served for this operation, and its broad or blade end cleared off the small filaments which arose from the outlines made by the stylus in the wax pre-paration. In the second method it appears that the wax colours, being prepared beforehand, and formed into small cylinders for use, were smoothly spread by the spatula after the outlines were determined, and thus the picture was pro-ceeded with and finished. By the side of the painter stood a brazier, which was used to heat the spatula and probably the prepared colours. This is the method which was pro-bably used by the painters who decorated the houses of Herculaneum and of Pompeii, as artists practising this method of painting are depicted in the decorations. This method has recently been revived in Italy. The third method was by painting by a brush dipped into wax liquefied by heat ; the colours so applied attained consi-derable hardness, and could not be damaged either by the heat of the sun or by the effects of sea-water. It was thus that ships were decorated ; and this kind of encaustic was therefore styled "ship painting."
About the year 1749 Count Caylus, and M. Bachelier, a painter, made some experiments in encaustic painting, and the count undertook to explain an obscure passage in Pliny, supposed to be the following (xxxv. 39) :—" Ceris pingere ac picturam inurere quis primus excogitaverit non constat. Quidam Aristidis inventum putant, postea consummatum a Praxitèle ; sed aliquanto vetustiores encaustics} picturae extitere, ut Polygnoti et Nlcanoris et Arcesilai Pariorum. Lysippus quoque iEginae picturae suae inscripsit Ivénavcnv, quod profecto non fecisset nisi encaustica inventa." There are other passages in Pliny bearing upon this subject, in one of which (xxi. 49) he gives an account of the prepara-tion of " Punica cera." The nature of this Punic wax, which was the essential ingredient of the ancient painting in encaustic, has not been definitely ascertained. The Chevalier Lorgna, who investigated the subject in a small but valuable tract, asserts that the nitron which Pliny mentions is not the nitre of the moderns, but the natron of the ancients, viz., the native salt which is found crystallized in Egypt and other hot countries in sands surrounding lakes of salt water. This substance the Carthaginians, according to Pliny, used in preparing their wax, and hence the name Punic seems to be derived. Lorgna made a number of experiments with this salt, using from three to twenty parts of white melted wax with one of natron. He held the mixture in an iron vessel over a slow fire, stirring it gently with a wooden spatula, till the mass assumed the consistency of butter and the colour of milk. He then removed it from the fire, and put it in the shade in the open air to harden. The wax being cooled liquefied in water, and a milky emulsion resulted from it like that which could be made with the best Venetian soap.
Experiments, it is said, were made with this wax in paint-ing in encaustic in the apartments of the Count Giovanni Battista Gasola by the Italian painter Antonio Paccheri, who dissolved the Punic wax when it was not so much hardened as to require to be "igni resoluta," as expressed by Pliny, with pure water slightly infused with gum-arabic, instead of sarcocolla, mentioned by Pliny. He afterwards mixed the colours with this wax so liquefied as he would have done with oil, and proceeded to paint in the same manner; nor were the colours seen to run or alter in the least; and the mixture was so flexible that the pencil ran smoother than it would have done with oil. The painting being dry, he treated it with caustic, and rubbed it with linen cloths, by which the colours acquired peculiar vivacity and brightness.
About the year 1755 further experiments were made by Count Caylus and several French artists. One method was to melt wax with oil of turpentine as a vehicle for the colours. It is well known that wax may be dissolved in spirit and used as a medium, but it dries too quickly to allow of perfect blending, and would by the evaporation of the spirit be prejudicial to the artist's health. Another method suggested about this time, and one which seems to tally very well with Pliny's description, i3 the following. Melt the wax with strong solution of salt of tartar, and let the colours be ground up in it. Place the picture when finished before the fire till by degrees the wax melts, swells, and is bloated up upon the picture; the picture is then gradually removed from the fire, and the colours, without being injuriously affected by the operation of the fire, become unalterable, spirits of wine having been burnt upon them without doing the least harm. Count Caylus's method was different, and much simpler:—(1) the cloth or wood designed for the picture is waxed over, by rubbing it simply with a piece of beeswax; (2) the colours are mixed up with pure water; but as these colours will not adhere to the wax, the whole ground must be rubbed over with chalk or whiting before the colour is applied; and (3) when the pic-ture is dry it is put near the fire, whereby the wax is melted and absorbs the colours. It must be allowed that nothing could well be simpler than this process, and it was thought that this kind of painting would be capable of withstanding the weather and of lasting longer than oil painting. This kind of painting has not the gloss of oil painting, so that the picture may be seen in any light, a quality of the very first importance in all methods of mural painting. The colours too, when so secured, are firm, and will bear wash-ing, and have a property which is perhaps more important still, viz., that exposure to smoke and foul vapours merely leaves a deposit on the surface without injuring the work. The " encausto pingendi" of the ancients could not have been enamelling, as the word " inurere," taken in its rigorous sense, might at first lead one to suppose, nor could it have been painting produced in the same manner as encaustic tiles or encaustic tesserae; but that it must have been something akin to the count's process would appear from the words of Pliny already quoted, " Ceris pingere ac picturam inurere."
Werner of Neuetadt found the following process very effectual in making wax soluble in water. For each pound of white wax he took twenty-four ounces of potash, which he dissolved in two pints of water, warming it gently. In this ley he boiled the wax, cut into little bits, for half an hour, after which he removed it from the fire and allowed it to cool. The wax floated on the surface of the liquor in the form of a white saponaceous matter; and this being triturated with water produced a sort of emulsion, which he called wax milk, or encaustic wax. This preparation may be mixed with all kinds of colours, and consequently can be applied in a single operation.
Mrs Hooker of Rottingdean made, at the end of the last century, many experiments to establish a method of painting in wax, and received a gold palette from the Society of Arts for her investigations in this branch of art. Her account is printed in the tenth volume of the Society's Transactions (1792), under the name of Miss Emma Jane Greenland. The following is an abstract of her processes:—
Put into a glazed earthen vessel four ounces and a half of gum arabic, and eight ounces or half a pint wine measure of cold spring water; when the gum is dissolved, stir in, over alow fire, seven ounces of gum mastic, continually stirring and heating hard with a spoon, in order to dissolve the gum mastic. When sufficiently boiled the mixture will no longer appear transparent, but will become opaque and stiff like a paste. As soon as this is the case, and the gum water and mastic are quite boiling, without taking them off the fire, add five ounces of white wax, broken into small pieces; stir and beat till the wax is perfectly melted and boils ; then take the composition off the fire, as boiling it longer than necessary would harden the wax, and prevent it afterwards from mixing well with water. When the composition is taken off the fire, it should be beaten well whilst hot (but not boiling) in the glazed earthen vessel; mix with it by degrees a pint or sixteen ounces more of cold spring water, then strain the composition, and bottle it. The composition if properly made should be like cream, and the colours when mixed with it as smooth as with oil. Mix with the composition on a china palette any powder colours which may be required to the consistency of oil colours; then paint with pure water. In painting with this composition the colours blend without difficulty when wet, and even when dry the tints may be easily united by means of a brush and a very small quantity of water. The painting being finished, heat some white wax in a glazed earthen vessel over a slow fire till melted, but not boiling; then with a hard brush cover the painting with the wax ; when cold take a moderately hot iron, such as is used for ironing linen, and which will not "hiss " when put to the usual test, and draw it lightly over the wax. The painting will appear as if under a cloud, till the wax and the substance the picture is painted upon are perfectly cold ; but if then it should not appear sufficiently clear, the wax may he melted by holding a hot iron at a proper distance from it, especially before such portions of the picture as do not appear sufficiently transparent or brilliant; for the oftener heat is applied to the picture the greater will be the transparency and the brilliancy of the colouring ; but the contrary effect would he the result were the heat applied too sud-denly, in too great a degree, or for too long a time. When the picture is cold, rub it with a fine linen cloth. Plaster surfaces re-quire no other preparation than a coating of the composition.
It would be equally practicable to paint with wax alone, dissolved in gum water. Take three quarters of a pint of cold spring water, and four ounces and a half of gum arabic, put them into a glazed earthen vessel, and when the gum is dissolved, add eight ounces of white wax. Put the earthen vessel, with the gum water and wax, upon a slow fire, and stir them till the wax is dissolved, and when the mixture has boiled a few minutes, take it off the fire, and throw it into a basin, as by remaining in the hot earthen vessel the wax would become rather hard ; beat the gum water and wax till quite cold. It is necessary to use some pure water in mixing this compo-sition with the colours. If the ingredients should separate when bottled, they have only to he well shaken together. This composi-tion may be kept for a long time, and be rendered fit for use by putting a little cold water upon it for a short time.
The following is a recent receipt. Place in a large pipkin, half full of hot turpentine, as much gum dammar as will dissolve (| lb gum makes about 1J pints varnish) ; melt from two to two and a half of the wax tablets sold by chemists in a pint of this varnish; when cold the composition should just be consistent enough to stand up on the palette. If too thin, heat it again, and add wax ; if too thick add turpentine. This vehicle may be used with ordi-nary oil colours. Before commencing your work heat the wall, and rub in as much vehicle as it will absorb ; after the work is finished it should be re-heated, to secure its adhesion to the wall.
See Lorgna, Tin discorso sulla cera punica; Pittore Vicenzo Bequeno, Saggi sul RistaMlimento dell' antiea Arte de' Greei e Romani, Parma, 1787 ; Phil, Tran., vol. xlix., part 2; Muntz on Encaustic Painting; Elmes's Dictionary of the Fine Arts;~W. Cave Thomas, Methods of Mural Decoration, London, 1869. (W. C. T.)