DAMAR is generally mentioned in the same breath as mastic, and in fact the two resins act in much the same way as far as painting is concerned. Damar solutions are as clear as water, which is an advantage, but damar is considerably more brittle than mastic, and also less fast to air and damp. Thus, varnishes made of damar sometimes cause a milkyblue "bloom" on a picture, which will disappear once the damp has been expelled. Mastic is therefore a better binder, its slight yellow tinge being hardly noticeable in combination with pigments.
TURPENTINE is a balsam secreted by conifers. The following kinds are differentiated for painting: Venice turpentine (larch), Strasbourg (silver fir), Canadian turpentine or balsam (Canadian fir) and the olio d'Abezzo from stone pines. Many of these cannot now be bought except at drugstores, but it is not really very important which tree the turpentine comes from. It should simply be as clear and transparent as possible and viscous, not crumbly and dry. Dropped into spirits of turpentine it should become thin.
Good turpentines are as good as resins for binders; they do not yellow, but they are slower to exude the spirits of turpentine in which they are dissolved and thus stay sticky longer. Balsams, particularly Venice and Strasbourg turpentine, are some of the best substances for quick drying emulsions.
There is a whole series of resins, such as copal and amber, which used to be in favor with artists. They are, however, dubious in effect in the picture, since they give such a brilliant shine that, in general, it is better today to avoid them.
WAX has so far been mentioned only as an additive to oils and resins. It is also a binder on its own and was much used in antiquity when it was the most weather resistant of all binders. Surprisingly enough, modern science has not yet been able to discover how wax was made sufficiently fluid in those days to be used at ordinary room temperatures for painting.
It is known that in preparation the wax was melted on the fire and the pigments added to it, but the hot wax color does not .remain liquid on the brush, and thus could not be applied to the picture. Even at a temperature of 104 degrees F., when the sweat is pouring from you, you will find that the wax stiffens on the brush between the pan on the fire and the picture, making it quite impossible to spread on the canvas. Brush marks on old wax paintings make it quite certain that wax colors were put on with a brush. Moreover, so-called "Punic" wax was used, which does not melt below about 212 degrees F., whereas unprepared beeswax needs only a temperature of about 147 degrees F.
Probably the solution to the problem lies in using a slowly evaporating medium which is liquid when cold, something like turpentine oil or petroleum. But if you try to keep wax liquid in this way at a bearable temperature it needs about 15 or 20 times the amount of medium as of wax; since the wax alone is the binder, it could in this solution only make very weak colors, and they would not hold very firmly to the ground.
This could be helped by warming afterwards, which would at the same time accelerate the evaporation of the liquifying agent. This was certainly done in antiquity, for there are traces of marks from iron spatulae to be seen on antique "encaustics" (wax paintings are called after the Greek word meaning "to burn in"). The brush marks show, however, that strong colored paints were applied at one time, rather than a long series of weak coats built up by overpainting.
I have tried this method, using wax thinned with turpentine, and found that sufficiently strong color effects could be achieved, which the transparency of the wax made very attractive. I would rather you did not ask, however, how long it took to put on the innumerable coats!
Certainly the antique encaustics were not painted in this way! Perhaps you can solve the riddle.
There would be no need to make such a fuss about this accursed wax were it not of such a perfect consistency, almost unalterable and of unlimited durability.
Wax has been found unaltered after 5,000 years. It does not yellow nor crack and is not sensitive to acids in the air nor to weathering nor water. It shrinks a great deal in high frosts, however, and would crack in high latitudes on an outside facade in winter weather. It can be seen how durable wax is from the paintings done on marble, where the areas surrounding the pictures have weathered, leaving the wax paintings themselves. unaltered and standing out like a flat relief on the surface of the stone.
If anyone succeeded in making wax usable for painting under normal conditions it would make all resins, oils, emulsions, and water-resistant gums superfluous; we should have a single, uniform, and completely unproblematical binder.
All this refers only to pure beeswax. The best kind is the so-called "virgin wax" from cells not yet used for hatching grubs, which is ivory white in color. This can rarely be obtained, except by lucky chance from a beekeeper. But even ordinary pure beeswax is good. It can be bought at good hardware stores. If it comes from a beekeeper it has to be purified in boiling water. All dirt sinks to the bottom of the cake of wax that forms over the water as it cools, and which can be scraped off.
Punic wax was obtained by boiling up the wax with sea water. When hartshorn salt was added, the caldum and magnesium salts combined with the wax and caused its higher melting point. If you wish to make Punic wax yourself there is no need to go to the expense of a trip to the Mediterranean, it can be done easily as follows:
Boil 50 gr. purified beeswax in 500 cc. distilled water and add 5 gr. soda which has been dissolved in a little water. This forms a kind of soap with the wax, into which is stirred enough of a 10 per cent solution of magnesium chloride to make the Punic wax fall out in more or less firm crumbs.
In antiquity this wax, under the slogan "punica est optima," was used as widely as linseed oil varnish is today for painting of all kinds. The underwater surfaces of ships were protected by coats of it. The few encaustics of an artistic kind which have come down to us are as fresh in color as though they had just been painted.