Bias lighting

Bias lighting is a low-intensity light strip placed behind a TV or projector screen, usually facing the wall rather than the viewer. Instead of lighting the room, it creates a soft glow around the edges of the display. This gives the eyes a reference point between the bright screen and total darkness, which is what actually reduces the strain of watching a bright display in a pitch black room.

It also has a visual side effect: because the eye judges black level relative to its surroundings, a screen surrounded by total darkness can make dark scenes look slightly grayish by comparison, while a soft bias light behind the screen makes the same black level read as deeper and richer. Many bias lighting kits use a neutral daylight-balanced white, around 6500K, to avoid tinting the picture's colors.

A common mistake is choosing a brightly colored or overly saturated light strip for aesthetics, which can subtly shift how colors on screen are perceived. Another is placing the light where it spills onto the screen surface itself rather than the wall behind it, which creates glare instead of the intended soft ambient glow.