Faux wood graining involves applying a solid paint colour overlaid by a translucent coloured glaze. You pull a graining tool through the glaze, removing it in stripes which provide the grain effect. Graining can be subtle or dramatic. The base coat should generally be several shades lighter than the top coat. You can grain using natural wood hues or in less realistic combinations -- for example soft greens or blues.
The base paint should be a matt latex finish as gloss paint would repel the secondary glaze. Artists' acrylic paint -- available from art supply or craft stores -- can tint the clear top glaze. Glaze is available at most hardware stores, along with wood graining tools. A graining rocker is the basic "starter" tool. This is a domed tool with raised rubber "grain".
Basic and Straight Grain
Brush glaze thinly over the dry base coat, in the direction of the intended grain. Brush in 6-inch wide sections, running the full length of the object. Grain this section before glazing the next 6-inch strip. Hold a graining comb or graining rocker at arms length, then pulled steadily towards yourself, in the direction of the "grain". If using a rocker, place this with the highest point touching the glaze, and pull steadily, without rocking. Comb each section through twice for a fine grain.
Coarse graining indicates the glaze is too thick. Wipe it off and reapply after dilution with a little more water. Blurring indicates glaze was applied too thickly. Use a brush to spread and to remove the excess. Comb again.
Pull a rocker towards yourself while slowly rocking it by tipping your wrist. At the start of the stroke the edge of the rocker closest to you should be touching the glaze. During the stroke it should tilt one complete time, ending with the top edge in contact with the glaze. Intersperse strips of heart grain with strips of straight grain for greater realism.
You can do knots using the heart grain technique but rocking more frequently. In the course of one stroke, the tool moves completely from bottom edge to top, several times. Too many knots can be distracting. Intersperse faux knotting with sections of straight graining. For softer effects, brush the still-tacky graining with a dry paintbrush.
Skilled wood grainers may use brushes to hand-paint grain or soften combed graining by gently slapping with a "flogger" or coarse brush. Brushes can also add stippling or by rotating with bristles splayed, make knots. The lighter marks that run across the grain in oak can be replicated by hand painting or by removing glaze with a rubber "silver graining tool".
Grain rollers, grain pads, fine steel combs, mottlers and check rollers make more detailed grains. Some are designed to imitate specific wood types. Check rollers add paint rather than removing glaze,. They create the under-grain and pores typical of oak and mahogany, before using a rocker for heart grain.