Yellow anemone in UV light. Photograph of yellow anemone (Anemone ranunuloides) flower coloured to show areas that reflect (yellow) or absorb (dark areas) ultraviolet (UV) light. This flower has petals with high UV reflectance, and stamens and pistils with high UV absorption. The UV pattern, known as a 'nectar guide', is thought to help 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 B800/2938 for normal daylight version.