Wood anemone in UV light. Coloured photograph of a wood anemone flower (Anemone nemorosa) showing areas that reflect (blue) or absorb (dark areas) ultraviolet (UV) light. This flower has petals with high UV reflectance, and stamens and carpels (centre) with high UV absorption. This pattern, known as a 'nectar guide', is thought to attract pollinating insects, which can see in UV light. This image was taken on a digital camera adapted to filter and detect UV light. The resulting monochrome image was coloured on a computer. UV light is invisible to humans and does not have a true colour. See image B800/2943 for normal daylight version.