Photosensitivity

Photosensitivity is the degree to which all species change color in response to natural sunlight or UV light. Depending on how much natural sunlight or UV light the wood is exposed to will determine how quickly and how drastically the change occurs. Whether finished or unfinished, wood changes color over time due to age, oxidation, and exposure to light. Some color change is to be expected for all species. Certain species, such as American cherry, walnut, and Jatoba, are notorious for drastic change in color. The intensity of the color change depends on many factors: the species, finish, exposure to various forms of lighting, and exposure to the particles in the air. Some species darken in color, some lighten in color, and some change color altogether, over time. Oak, maple, hickory, walnut, and many other domestic species generally will fade in color and/or amber as the finish/stain is affected by the UV light. Generally, tropical/exotic species will darken and richen in color with exposure to UV light. Species are classified in this publication based on how drastic they can change color, as being low, low-to-moderate, moderate, moderate-to-high, or high.