E Ink's technology is commonly referred to as "bistable". Bistablility refers to the fact that an image on an E Ink screen will be retained even when all power sources are removed. This means that the display is consuming power only when something is changing. For example, when reading on an eReader, power is only needed when turning to a new page but no power is consumed by the display while reading the page. Bistability significantly reduces the power consumption and is a key reason devices using E Ink have such long battery life. The larger ePaper screen, the more electronic power can be saved compared with the same size LCD screen.

E Ink displays are referred to as "reflective displays." In an LCD, or "emissive display", light from a backlight is projected through the display towards your eyes. In an E Ink display, no backlight is used; rather, ambient light from the environment is reflected from the surface of the display back to your eyes. As with any reflective surface, the more ambient light, the brighter the display looks. This attribute mimics traditional ink and paper, and users of E Ink displays have said that they do not have the same eye fatigue as with LCDs when reading for long periods of time. Eliminating the need for a backlight significantly increases the battery life versus using a traditional LCD.