Electronic paper refers to several reflective display technologies that do not require a backlight and can be viewed in conditions of good ambient illumination. Bistable pixels — that remain in a particular state after the power is removed — are used. For static images, this results in ultralow energy consumption. Most electronic paper technologies involve physical movement within the pixel to facilitate a change from light to dark, or to change color. The performance achieved has therefore been slower than with other displays, such as LCDs.