Please discuss coloring wood–aniline dyes etc. What finish will not cut the color? — Gary Bashian
Bruce Hamilton replies: Wood can be colored with pigments and dyes. The most vibrant colors are achieved with dyes. They are transparent and reflect more light. Their small molecular size permits deep saturation into the wood fibers. Aniline dyes where used for many years. These are a derivative of coal tar and are toxic. Now all dyes for wood coloring are synthetically created.
Dyes come in powder and liquid form. Dye powders can be dissolved in water, alcohol and solvent but each powder is solvent specific and you must use the right solvent with the right powder. Of the powder based dyes water dyes are the most like fast and easiest to apply. Water based dyes can be sprayed on and the excess wiped off to achieve a fairly uniform application. When alcohol based dyes are used they tend to show lap marks because they dry so quickly. The drying rate of solvent based dyes can be adjusted depending on the solvent used. Mineral spirits is slow drying, Naphtha or acetone are faster.
Pre-mixed liquid dyes can come diluted like Behlen’s Solar-Lux or concentrated like Jeff Jewitt’s Trans Tints. Solar-Lux dyes and the Trans Tint dyes are metallized solvent dyes. According to Jeff Jewitt, these dyes are the most light-fast available and more bleed resistant then the powder dyes.
When it comes to finishing over colorants like dyes, the one finish that I believe will enhance the colors the most is shellac. Shellac has the smallest molecules of all the common finishing materials and can penetrate deep in to the wood fibers. Shellac gives the surface a crystal like appearance when light hits it. It is important to use de-waxed shellac that is light in color such as Super-blond. Other formulations of shellac can be very amber and the wax they contain may cloud the appearance of the color and diminish the sheen.