Staining wood is not the only way to add color to a finish. In fact, most commercial furniture finishes are colored in layers. After the stain and first clear coat have been applied, you can change the tint, go darker or whiter or add age, depth and highlights. It’s all done with glaze, toner or a combination of the two.
Of the two, toner is both simpler to use and more intuitive. If you think of finish as a clear film applied in liquid form, toner is nothing more than a tinted film applied the same way. Typically, toner is applied after the first coat of clear finish and before the last. Most clear finishes can be made into toner by adding small amounts of color, and in many cases, that has been done for you. Finish companies sell toner in aerosol cans, but you can also use tinted waterbased and oil-based polyurethane, such as “One Step Stain & Poly,” as brushable toner. It’s best to use tinted water=based polyurethane with waterbased clear polyurethane and oil-based versions with oil-based varnish and polyurethane. Aerosol cans of toner can go between layers of lacquer, shellac or water-based finishes and, if applied lightly, even with oil-based coatings.
The main challenge with toner is applying it evenly. It’s not all that obvious when a clear finish is thicker in one spot than another, but variations in toner thickness will show up as darker and lighter bands of color. For that reason, it is a good idea to practice with toner on scrap first. This is especially true with aerosol toners, which can sometimes add a surprising amount of color very quickly.
Glazing, on the other hand, is a similar means of adding color to your project. It uses the same basic materials as stain, but you float them in a thin layer between coats of finish.