[CHAPTER III]
Painting (elementary)—Pigments—Mixing—How to Fill the Brush—Outline—Examples—Industry—The Needle and Stick—Completing the Outline.
The pigments for painting on glass are powders, being the oxides of various minerals, chiefly iron. There are others;
but take it thus—that the iron oxide is a red pigment, and the others are introduced, mainly, to modify this. The red pigment is the best to use, and goes off less in the firing; but, alas! it is a detestably ugly colour, like red lead; and, do what you will, you cannot use it on white glass. Against clear sky it looks pretty well in some lights, but get it in a sidelight, or at an angle, and the whole window looks like red brick; while, seen against any background except clear sky, it always looks so from all points of view. There are various makers of these pigments. Some glass-painters make their own, and a beginner with any knowledge of chemistry would be wise to work in that direction.
I need not discuss the various kinds of pigment; what follows is a description of my own practice in the matter.
To Mix the Pigment for Painting.—Take a teaspoonful of red tracing-colour, and a rather smaller spoonful of intense black, put them on a slab of thick ground-glass about 9 inches square, and drop clean water upon them till you can work them up into a paste with the palette-knife (fig. 18); work them up for a minute or
so, till the paste is smooth and the lumps broken up, and then add about three drops of strong gum made from the purest white gum-arabic dissolved in cold water. Any good chemist will sell this, but its purity is a matter of great importance, for you want the maximum of adhesiveness with the minimum of the material.
Mix the colour well up with the knife; then take one of those long-haired sable brushes, which are called "riggers" (fig. 19), and which all artists'-colourmen sell, and fill it with the colour, diluting it with enough water to make it quite thin. Do not dilute all the pigment; keep most of it in a tidy lump, merely moist, as you ground it and not further wetted, at the corner of your slab; but always keep a portion diluted in a small "pond" in the middle of your palette.
