Chatoyancy (shə-TOY-ən-see)
Chatoyance in wood is a shimmering effect that occurs when light interacts with the wood’s grain, creating an illusion of depth. This effect is often seen in figured woods like curly maple, where the wavy grain patterns cause light to reflect differently at various angles, resulting in a lustrous, jewel-like appearance; often seen on guitar tops. The piece below is rare figured teak.
In gemology it is also called the cat’s eye effect, an optical reflectance effect seen in certain gemstones, such as Tigers Eye. Historically, chatoyancy has been applied explicitly to gems. In wood, the effect is more broadly known as ‘figure’ or iridescence, but neither of these terms properly describe what happens when light hits wet or finished wood. (see below)
Many woods exhibit some level of chatoyancy overall when wet or finished, especially Koa, Okoume and Sapele. Click here https://www.chatometry.com/ for a deep-dive into wood chatoyancy on 521 species, including chatoyancy levels and actual videos showing the effect in many species.
The most prized woods have highly chatoyant pockets or (rarely) in whole logs caused by ‘figuring’. This can occur in various species, but particularly in hardwoods. Stresses from the weight of the growing tree, damage or disease can result in denser patches causing wavy grain, burl or ‘bird’s eye’. This ‘figuring’ can create a striking three-dimensional appearance of depth and play-on-light similar to iridescence. This is featured regularly in musical instruments and decorative wood products. Figuring takes on a variety of forms and is referred to as flame, ribbon, tiger stripe, and quilting among other names.
Wetting wood with water often reveals its chatoyancy, but only until the wood dries. Some finishes can amplify this effect, including oil finishes and shellac, but clear epoxy or lacquer give the best results at magnifying the appearance of depth in the wood’s figure.
List of Chatoyancy Figure Patterns
- Bird’s eye: Small, eye-like patterns usually found in maple.
- Burl: An abnormal growth with a random swirling or roiling pattern.
- Fiddleback, Flamed, Tiger or Ribbon Striped: A wavy, striped pattern that resembles flames or tiger stripes. It’s commonly found in maple and is often used for guitar tops and other decorative purposes.
- Quilted: This has a distinctive pattern that looks like a series of bubbles or diamonds. It’s often described as having a mosaic or quilted appearance.
- Ray fleck, Ribbon Fleck or Flake: A shimmering, ribbon-like pattern or flecks that run perpendicular to the grain caused by medullary rays in wood, particularly in quartersawn lumber.
How to Enhance Chatoyancy
The best way to enhance the chatoyance effect is through a clear coat of lacquer or epoxy. Shellac can give good results if applied to high sheen but can darken the wood. Low-gloss and flat finishes can work but lessen the effect.
Dyes are another good option, often seen on guitar finishes. Dyes can penetrate the wood’s cell structure, accentuate the figure and add depth to the chatoyant appearance. A common method is to use a dark color like black or brown, let it soak in and dry, then sand off most of the dye. Other, lighter colors can be then added for the desired effect. This darkens the deepest part of the figuring and enhances the appearance of depth. This is most often seen on guitars.
Angle of Viewing
Chatoyance is most noticeable when viewed from or lit at different angles, as the color and pattern will change depending on the viewer and light’s position. Because of this it is important to consider the piece of wood and its positioning in the project to maximize this effect. Curved pieces often work best, as little movement is needed to reveal the effect. When used in a flat piece like an end table, be sure the wood is positioned to best reveal its figuring. A board may “pop” when viewed from one direction and reveal nothing from another.
The Definition of Iridescence
Describing wood as iridescent to denote ‘figure’ or chatoyancy is inaccurate. The primary definition (below) includes “rainbowlike” colors – no wood does his.
Iridescence: a lustrous rainbowlike play of color caused by differential refraction of light waves (as from an oil slick, soap bubble, or fish scales) that tends to change as the angle of view changes.
The Definition of Figure in Wood
‘Figure’ is a broad term that describes any wood with an interesting or unique grain pattern. This may or may not include chatoyancy. Click Here to see a full breakdown of “Figure”.