Low-key and High-key. Black and White. Polar opposites. Each one defined by the absence of the other. That is the story of low and high-key lighting when it comes to portraiture, whether it is people you are photographing or still life. Each has a distinctive and telltale characteristic that is easily discernable.
When low-key and high-key lighting are described in technique, it is safe to say that low-key lighting requires at its most basic, only one light source, whereas high-key lighting may need an array of lights to be completed successfully. But that is not nearly the truth. There is a tendency to describe low-key lighting as being “dramatic” but both can have a powerful impact if done right. It’s likely the idea of drama in low-key lighting probably originates in the theatre where high-key lighting can be difficult to accomplish when drama is of the essence, and in the early days of theater companies it was necessary to create illusion with as little cost as possible, hence the one light trick.
To create a low-key image, all you need is your camera and one light source really. The first idea is to keep you ISO as low as possible to avoid noise in shadow areas, because shadows, the black end of the spectrum, are going to be the dominant tone. There is going to be lots of “negative” space in your picture.
Photo Courtesy of James Schuck
Any light source can be used effectively and good low-key lighting does not always have to be limited to one light source. When a subject is set in front of a black background, it is important to make sure that no light spills onto your background. But it’s still possible, particularly if your subject is wearing a dark jacket to use a second light source as a “hair light” to separate subject from background. Hair lights can be effective with people who have dark hair and unnecessary with blondes and people with no hair at all. In the photo above, it would have even been possible to use a third light to the left of the picture to create even more separation. If you wanted to go completely crazy, a fourth light coming directly from above on the subject’s hair would have been perfectly reasonable, and you could still call this a low-key setup. Low-key lighting does not mean less light, it means making a decision to create an image in which dark tones dominate and that can be accomplished with one light or many. It is the judicious use of light that is most important. In the photograph above, a large softbox lit the subject from the front and one smaller softbox added the separation from the side.
If low-key lighting is all about dark tones, high-key lighting is all about light. Bright light. Lots of white, or “positive space” and very little in the way of dark tones.
Photo Courtesy of James Schuck
The portrait above is a classic example of high-key lighting. There are no shadows to speak of; everything is way up in the highlight end of the histogram and virtually nothing down at the black end, exactly the opposite of the low-key portrait in the first example. There is no detail in the background and the foreground (the young girl’s dress) contains just enough detail to create some tonal separation. There are two ways to go about creating a background that is devoid of any highlight detail. The first would be to shine lights, maybe one to each side behind the subject, illuminating a white seamless, or in this case, the photographer placed a single flash head behind a transparent background behind the subject. It created an evenly lit background and provided more than enough hair/back light to surround the subject. The main light was a large softbox that was calibrated to an exposure perhaps one-half to one full stop under the backdrop exposure. Two lights. The same setup as with the low-key photo described above; the same lights used very differently creating dramatically different images.
See more: High Key Lighting Secrets Revealed
The most important element of lighting, whether it be low-key or high-key, is consideration of subject matter and using what best applies to light that subject, whether it is animate or inanimate. It is not a question of how many lights, but how you use them. Be sensitive to your subject. Ask yourself what tonal values best describe this person or that object. In photography, we are essentially limited to ten basic tones. Does your lighting choice best lend itself to describe your subject? Is your subject high or low, or somewhere in between? Notice in the photographs above that consideration was given to clothing choices that were sympathetic to the lighting choice. Or was it the other way around? Would the same results have been achieved if the lighting choice had been switched? These are all questions you should be asking yourself when it comes to lighting. Certainly there are “signature” lighting setups that define good photographers, but the very best photographer chooses lighting based on subject, not on their own personal choices. Sensitivity to subject is the key to successful photography. Knowing when to use certain kinds of light is the essence of a successful photography business. By the way: one of these photographs was made in the photographer’s studio, the other in the subject’s living room. Can you tell which is which? Look for another blog where studio is very loosely defined and can be anything from your client’s kitchen to the opulence of a studio with enough room to photograph a car in.