A true Day/Night Network Camera has separate image processing systems for normal and low-light conditions. Some of these night-vision network cameras can produce reasonable images in extremely low light levels, where the human eye could not react. The images produced under low-light conditions are almost always monochrome rather than the colour produced during normal lighting conditions. These day/night IP cameras can usually be enhanced even further by the addition of infra-red illumination, which is picked up by the camera but is invisible to the human eye.