Visual texture, also referred to as "implied texture", is not detectable by our sense of touch, but by our sense of sight. Visual texture is the illusion of a real texture on a two-dimensional surface. Any texture perceived in an image or photograph is a visual texture. A photograph of rough tree bark is considered a visual texture. It creates the impression of a real texture on a two-dimensional surface which would remain smooth to the touch no matter how rough the represented texture is.