Umbers, natural pigments consisting of a mixture of clays and brown hematite, are valuable on account of their transparency and of their good drying qualities when in oil; the latter qualities are so pronounced that umbers may be employed as drying agents. Raw umber is unsurpassed as a graining color for light imitations, whilst burnt umber may be used for antique oaks from light to the darkest. In mixing grounds, also, umbers are invaluable. Raw umber does not injure colors with which it is mixed. Burnt umber is very permanent, and is sometimes used instead of Vandyke brown.

Raw sienna is the yellow pigment used for very rich and light oak, but, properly, should seldom be required, as decided yellow and bright tones are not characteristics of real oak. The siennas are used in oak colors to produce a forced richness. Similar in nature and preparation to the umbers, they are more transparent, but lack the natural drying qualities of umber when used in oil. Siennas are used to produce those imitations which are obtained by the use of pigments ground in water; they are useful for graining in mahogany, maple and walnut. Raw sienna is rather an impure yellow, but has more body than the ochres and is also more transparent. By burning it becomes burnt sienna, which has similar properties. Burnt sienna is a rich, transparent and red-brown pigment; gold size may be used as a drier with it. It dries better than raw sienna, and is very permanent, as it is not liable to change by the action of light and oxygen, or by damp and impure air.

Vandyke brown, a transparent earth pigment, is a very slow drier, and, if used in oil, requires to be diluted with a drying agent. It has a dark color, inclining to neither yellow nor red, but yet extremely rich and deep. In oak graining, it is generally ground in water, its color being warmer and richer than when used in oil. It is the principal pigment used in overgraining oak. It is a bog earth.

Neutral blacks and blues, previously mentioned, are also to some extent transparent. Blue-black in conjunction with Vandyke brown is largely used for overgraining oak. Black enters into the composition of the dark grounds for antique oak. The effects of transparent blues may be regarded by some grainers as questionable, but it must be remembered that richness of color in woods is only a matter of comparison and contrast, and, therefore, if instead, of forcing the color values by bright grounds, bright graining color and rich overgraining, some contrasting cool tones are introduced, it is possible to obtain more natural color variety and yet retain the subdued contrasts of the real oak. Prussian and indigo blues are vastly different when ground in water from what they are in oil; whilst the tints are considerably mellowed by the final coating of copal or oak varnish. The first stages of oak graining should be worked in subdued tones rather than in false bright ones, and any desirable enrichment should be left for the glazing and overgraining to accomplish in preference to struggling in the final phase to modify early faults.

Megilp is added to oil graining color to, ensure that the latter shall not spread when combed. In ordinary and cheap oak graining an excess of the drying agent is made to serve the purpose, but the megilp generally acknowledged to give the most satisfaction is a preparation of beeswax. A few ounces of pure wax is shredded and dissolved, by the application of heat, in linseed oil; add to the dissolved beeswax 1 pint each of linseed oil and oil of turpentine, 1 gill of patent dryer and the pigments ground in oil. The wax must be thoroughly mixed with the other constituents, or the drying qualities of the color will be affected. It must be remembered that wax is not added as a drying agent, but solely to make the color more amenable to the dividing and wiping-out action of the combs.

Distemper graining pigments are bound by the use of beer. Vandyke brown, however, does not require a binder for overgraining in water, nor do the siennas very often. When using black or the cool tones, either alone or in combination with warmer colors, a little beer is necessary, because black has no binding power; if mixed with Vandyke brown in equal proportions no binder will be required, but it is always best to ensure that the overgraining will not work up when the varnish is applied. In finishing antique oak in black alone, the wash must be strong in beer; for mixed washes, one-half beer is a safe proportion.

For very light oak, the ground color is made from white-lead paint, and is tinted to a decided cream with yellow ochre. The graining color may be stained with raw sienna and raw umber, or the latter alone; the work may be over-grained in water with Vandyke brown and weak blue-black, or indigo.

Ordinarily light oak requires a clean buff ground, stained by ochre, and occasionally a touch of Venetian red or umber. Raw umber is suitable for the graining color, though burnt umber gives a richer cast. For the overgraining, Vandyke brown and blue-black are used.

Medium oak looks best on a warm buff, the red and ochre therein being slightly toned down with umber. Burnt umber alone makes a good graining color, whilst Vandyke brown is generally sufficient for shading.

The grounds for dark oak are best made with three pigments, ochre, burnt sienna and burnt umber. In this mixture red should show 'prominently, but it should, together with the yellowness, be sobered by the umber. For the graining color, burnt umber or burnt sienna and black may be used, overgraining with washes of black and Vandyke brown, used either separately or together.