In photography, if you want to create a certain kind of mood, one of the things that you can do is use high and low key effects. These effects are important if your intention is to be as creative as you can be and play with the atmosphere and style of your photos.
But there’s more to high and low key photography than white backgrounds and lower or higher contrast.
High key lighting was used to help improve high contrast ratios. It is important to note, however, that the concept of key lighting started in the film industry. Cameramen used the term key light whenever they referred to the main light used for a particular scene. Along with the key light, the cameramen would also use backlight and fill light to complete the lighting effect that they envisioned for the scene. Of course, nowadays, more sophisticated lighting technology is used in movie-making, so the three-light technique, while still in use today, has paved the way to more complex lighting setups.
Low-key lighting, on the other hand, produces images that are the opposite of high-key photos. The low-key technique uses a lot of darker tones, shadows, and blacks (the really deep ones). Photos are taken in low-key lighting, therefore, have very minimal amounts of mid-tones and whites.
Images taken in low key lighting create a mysterious and dramatic mood. They can display a varying range of deep negative emotions. Of course, the over-all effect depends on the scene, the subject, and the theme being portrayed.