The plants rich in chlorophyll absorb light in nearly all wavelengths of the visible spectrum; only reflect light around the fringe of 510nm (green), where not perform photosynthesis. The bulb Agrolite Darknight is a high power halogen with a specially designed filter to eliminate all wavelengths respecting this and is thus allowed to work in greenhouses and crops inside during the hours of darkness, allowing vision in the most humane and the life cycle of plants.