- High Key is a term to describe images that are bright and contain little to no shadow. The term comes from the early days of broadcast television when scenes with higher contrast were not reproduced well. To make a scene that was easier to properly show on screen, the ratio between the key and fill lights was minimized. It is also sometimes used to describe photos and the photographic style that is simply bright, often with an overexposed background.
High Key Photography
In photography today, a high-key image is one that is almost entirely very bright with very little or no dark shadows present. This is usually a creative decision made by the photographer, in order to create a certain mood in the image.
A bright, "airy" image most often creates a light, pleasant mood, as opposed to a dark, shadowy image which most often creates a dramatic, romantic, or even scary mood. A good photographer knows how to use not just lighting, but also pose and composition and other elements to create an impactful high-key photograph.
It may sometimes be as easy as over-exposing an existing scene by two or three stops, however often a proper high-key image requires careful attention to the balance of light between subject and background, often preserving detail in the subject while nearly or totally blowing out much of the background.
High-key portrait photography can be accomplished using multiple flashes, one for the "key" light, and one for fill light, plus others. Also, high-key images can easily be created using a single light source and other light modifiers such as reflectors or ambient light, to fill a subject's face etc.
High-key sample photographs