The Practice of
Tempera Painting - Pigments and Brushes

Grinding the Colors
Pigments are usually sold in the form of powder, and before they are ready to be used for tempera painting they need to be ground with water. Fine as the powders seem to be, most of them are not fine enough to paint with without further grinding; and all of them need intimate mixing with water, whether they are fine enough or not. Grinding one's own colors has a romantic sound; but I do not set any particular store by it. It is a laborious and messy business; and a friendly color manufacturer will generally consent to grind colors in water at no great extra cost. If, however, you wish to grind them yourself, you must obtain a slab and muller. The best material for these is, as Cennino says, porphyry. Failing that, granite is good. Porphyry and granite implements, however, are usually extremely expensive; for they have to be made to order. A marble table top will do for a slab, and a small lump of marble for a muller can be got out by a stonecutter at small expense. Simplest of all, however, is to buy a glass muller from a dealer in scientific laboratory supplies. It should have a three-inch grinding surface, and you will [p. 89] want a piece of ground plate glass about eighteen inches square. The glass or marble will wear down, and have to be resurfaced; but they serve well enough for grinding any but very hard pigments.

To put a good edge on the slab and muller, take some medium fine emery powder and throw it on the slab. Wet it to a thin paste with water, and grind it round and round, with a slight rocking of the muller, hardly more than a little extra pressure on the nearer edge. Wash off the emery, and grind your pigment in the same way, mixed with water to a thin paste. It does no good to stir the color with the muller: it must be ground. You will soon develop the knack of keeping color between the grinding surfaces and off the sides of the muller. Add water as you need to, while grinding to keep the right consistency. The muller should move freely, but the pigment must be fairly creamy or pasty, or it will not be ground properly.

For gathering up the color after it is ground (and there is no rule but experience for how long to grind each color) you scrape it up into a little heap, and put it into a color jar. For this you will want a small wooden slice, a strip of hard wood cut like a chisel at one end. This is much better than a spatula, and enables you to clean the slab up almost perfectly, with almost no waste of the ground color. After grinding, wash the slab immediately, with a sponge and warm water and soap; and if it is not perfectly clean, grind some emery powder on it again. [pp. 88-89]

Storing Colors for Use
For keeping the colors after they have been ground, it is desirable to have wide-mouthed bottles with air-tight covers. The color is put in in the form of a paste, and the bottle filled up almost to the top with water. It must never be allowed to dry out, or the color will become granular and have to be reground. It is not a bad plan to use rather small bottles, grinding only a small amount of color at a time. You do not use any great amount of pigment even in a large painting, and there is less danger of contamination if the supplies of [p. 89] color are renewed from time to time. If you buy your colors ready ground in water, it is advisable to transfer a little of each from the manufacturer's containers into small bottles of this sort. From a druggists' supply house you can obtain excellent little two- or four-ounce wide-mouthed bottles with screw covers made of bakelite. Tin covers are less good, because they often rust. The bottles should not be more than half filled with the ground color, so as to leave plenty of room for water above. Small quantities of fresh color are much more convenient than large jars which have collected dust and traces of other colors, and I recommend the two-ounce screwcap bottles for ordinary use. It is convenient, though not necessary, [p. 90] to have a box or stand to hold the color jars, so that they are always in order, and kept from tipping over. A length of two-by-four with sockets cut in it to fit the jars makes a satisfactory rack for them. [pp. 89-91]

Dishes for Mixing
For mixing the colors in painting, nothing is better than the nests of porcelain color cups used by architects. It is an advantage to have a generous supply of them; two dozen is not too many, though you can do with less. The covered porcelain trays with eighteen or twenty-four cup-shaped hollows in them are also useful: and for small paintings one or two of these do just as well as the more costly sets of color cups. For large works, that is, for panels of more than six or eight square feet, it is a good plan to buy a generous supply of small white bowls; or cheap, heavy whisky glasses will do well enough, and cost less. [p. 91]

The Choice of Brushes
The choice of brushes for tempera painting will be regulated to some extent, of course, by the size and type of the painting; but whether the brushes are large or small, blunt or pointed, bristle or sable, they must be designed to hold a certain body of color and to feed it out in painting as freely and smoothly as a pen feeds ink. This means that the hairs or bristles must be fairly long, and nicely toed in to the point, so that the natural curve of the hair forms a reservoir between the ends. Nothing is better than red sable water color [p. 91] brushes. It does not pay even to experiment with camel's hair; it is too soft and unmanageable. Black sables are a little less expensive then the red, but much inferior, not only in the hair, but usually also in the workmanship. Curiously enough, breadth of treatment in tempera has not very much to do with the size of the brushes. You can work as minutely or as broadly as you please with a small brush; and for the beginner, small brushes are usually an advantage. Japanese or Chinese brushes, made of fiber or sheep's hair, are of limited usefulness for tempera painting. they make beautiful strokes with very thin color; but have not enough spring for general use. [pp. 91-92]

Sables
It pays to buy the best brushes, and to take good care of them. Fine English-made brushes of red Russian sable are very costly, but extremely good. Some American makes are now equally satisfactory. One pays a good deal for the nicely finished handles and nickel ferrules of good water-color brushes, however, and it is a great economy to buy the brushes in quills. Beautifully made sables in quills, used in America chiefly by sign painters, cost much less than the finished artists' brushes, and are every bit as good. One must, of course, take the trouble to soak the quills for a while in warm water, to soften them, so that they will not split and break when the handles are pressed into them; but that is a small matter.

Anyone who does much tempera painting will want to keep on hand a good supply of these brushes. It is good practice to use a fresh brush for each mixture as you paint ; and if this is to be done, two or three dozen brushes will often be in use together. It is not necessary: you can do the whole job with one brush. But it is a much better plan to use many brushes, so that the tones are kept separate, and you do not need to be washing out your brush constantly as you work. And the brushes will wear down more slowly and evenly. Three dozen brushes bought at once will outlast three dozens bought separately, and give better service. If possible, build up a good stock of brushes quickly, and add a few every once in a while so that your supply gets a little better all the time. When not in use sable brushes should be kept in a tin box with a few flakes of naphthalene.

Brushes should ordinarily be round. Flat brushes are not so useful as one might expect. They make a broad stroke, it is true; and it might seem as if they would be quicker for laying in a tone. Actually, they are not. They do not hold so much color as round brushes; and though the stroke is broad, it is often not even. The size of brushes, too, is apt to be a little deceptive in this matter of speed. Large sable brushes tend to lay a coat thicker, but not necessarily faster. So much depends on neat manipulation that a skillful painter can lay in a tone with a small sharp pointed sable faster than a careless painter with a much larger and apparently more suitable tool. [pp. 92-93]

Bristles
For broad areas, however, it is obviously unsuitable to work with a small sharp point. For large pictures, it is valuable to have some good bristle brushes; for they can be made with a broader, blunter point than the sables, and so produce a stroke better proportioned to a large scale of detail. It is not easy to obtain suitable bristle brushes, however, Artists' oil brushes are, for the most part, worthless for tempera. Up to the middle of the nineteenth century, oil colors were generally used fresh, ground by hand, with a good proportion of oil, and were in general fairly liquid. Brushes in those days were designed to hold enough of this liquid paint to make a long, smooth stroke. When colors began to be ground by machinery and packed in tubes, and kept, the proportion of oil was soon reduced; for manufacturers found that the pigments settled out of the oil, and their patrons complained. Cutting down the amount of oil did not solve the difficulty, and it was found necessary to put in wax and other materials, such as alumina and aluminium stearate, to [p. 93] Keep the color in suspension and to make it "set up." This sort of oil paint, however, did not flow from the brush. It had to be pushed into place on the canvas. And consequently the form of artists' brushes changed. Long bristles were an nuisance in handling this soft, plastic material; and round brushes spread it less neatly than flat brushes. The artist's bristle brush has changed within a hundred years from a pencil to a spatula. The thin, flat, straight, short-bristled brushes which are common today are as different as possible from the plump, long, springing brushes of the eighteenth century. There are, however, fortunately a few brush-makers who still offer well-made brushes with a good length of bristle.

Bristle brushes for tempera should be round, and very long in the hair in proportion to the diameter: as much as two inches of bristle is not excessive in a brush the size of a lead pencil, or a little larger. For the point to have any shape, a brush of this sort must be made from bristles of high quality, carefully graded, and accurately toed. This means that it must be expensive; and brushes of this sort are expensive. But with care and washing, they will last a lifetime, and pay rich dividends in satisfaction. They improve with use, and the more they are washed with soap and water, the better. The points may be rubbed with sandpaper or emery cloth if they do not give a smooth stroke; for the "flag" [the divided end of the bristle] is of no value except as an indication that the brush has not been made from cut bristles. [pp. 93-94]

Care of Brushes
Do not make the mistake of supposing that you can let tempera color dry in a brush and wash it out afterward without injury. Tempera colors turn quite insoluble after they dry; and if they once harden in the neck of the brush, around the ferrule, it will not be long before the hairs begin to splay and break. Wash you brushes after use with mild soap and water, and take particular pains to squeeze the color out of the neck. Wash the soap out thoroughly, [p. 94] and dress the point nicely. If you take good care of good brushes, they will last for years; but if you do not, they can easily be ruined in a week. Do not try to repair a brush injured by abuse. If the point is winged, so that it makes two lines instead of one, throw it away. If stray hairs stick out, leaving a gap in the arch of the brush, throw it away. If the hairs break off at the ferrule, and the brush accordingly loses its spring and its capacity, throw it away. Do not give storage room to a brush in bad condition. Painting in tempera with a poor brush is exactly like trying to write with a broken pen--it cannot be done well. [pp. 94-95]