This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
This branch of the painter's art consists in imitating the grain, knots, etc, of different woods. The following is an outline of the process. If there are any knots or sappy places in the article, they should be covered with one or two coats of glue size, or parchment size, to prevent them showing through. The work is then ready for the paint, three different shades being necessary. These are called the ground colour, the stippling colour, and the graining or oil colour, and they are laid in the order named. An infinite number of combinations of colours is possible, obtained by the use of various colouring pigments in the different coats, and no two grainers agree as to the precise proportion of the ingredients to be used in imitating different woods; the learner can vary the proportions to suit his taste, as experience dictates, and to suit the work in hand. The ground colour is used to represent the lightest part of the grain of the wood, the stippling colour the intermediate shades, and the graining colour the darkest parts; a close study of natural woods will, therefore, be necessary to determine the colour and depth of each. The proper ground being selected, apply one or more coats - as many as are necessary to thoroughly cover the surface.
As soon as the ground colour is hard, the stippling coat may be applied. This is prepared by mixing the dry pigments without oil, with either very thin gum-water, stale beer, or vinegar containing a small portion of dissolved fish-glue. The pigments to be used are usually about the same as those used for the ground colour, but of different proportions to produce a deeper shade. Apply the stippling colour, and before it dries beat it softly with the side of the stippler, the long elastic hairs of which, disturbing the surface of the laid coat, cause the lighter coat beneath to become indistinctly visible, and produce the effect of the pores of wood. Next apply the graining colour; as soon as it is laid, take the rubber and with it wipe out the larger veins to be shown, after each stroke wiping the paint from the rubber with a cloth, held in the other hand, for that purpose. Some grainers use a small sponge for veining, and others a small piece of cloth over the thumb, but the rubber is probably the most convenient.
When the veins have been put in, to imitate as closely as possible the markings of natural wood, the various steel combs are brought into use, and the edges of the veins, and sometimes other portions of the work, combed with them, to soften the abrupt transition from the dark to the lighter shades. The blender is also now brought into use, and wherever the work may require it, the colours are still more softened and blended by its soft hairs. When too much colour has been removed in veining, or when a certain figure, such as a knot, is required, the work is touched up with a fine brush, and again softened with the blender. When dry a coat of transparent varnish should be applied, having considerable oil to render it durable, as grained work is frequently washed. Ready-made graining colours are recommended as best and cheapest.
In ground colours the essential condition is to have them light enough; the same tint will do for ash, chestnut, maple, light oak and satinwood, but a deeper tone is needed for black walnut. The most important point is to have the ground smooth and uniform. Graining colours should be chosen from the very best qualities of umber, sienna, and Vandyke brown, according to the demands of the work.
The implements employed by the grainer comprise, in addition to the ordinary painters' tools (a dusting brash and 2 or 3 flat fitches) for applying the graining colours to the groundwork, a badger-hair blending brush or softener, a set of combs, overgraining brushes suited for maple and oak, and a camels'-hair cutting brush for maple. You may add a large cotton rag, a sponge, a lining tool, a veining horn, and combing and graining rollers. The combs may be of steel or leather. A set of steel combs contains 3 of each size - 1-in. wide, 2-in., 3-in., and 4-in., of fine, medium, and coarse teeth. A cloth put round a steel comb is often substituted for a leather comb.