In this article, I will dive down the rabbit hole to try and explain some of the most common light functions in portrait photography.
Before I go any further, let me say that these are my views on light roles and the best way to apply them. This is not a way of looking at light roles in still photography. The light can either be placed in an important position or in a crucial position. Each light can be used in a variety of ways, depending on the creativity.
This is the most important light in the picture and ideally, it is the most visibly present light in the image. If you are shooting for an Arabic audience, it is a good idea to place your key left to right.
The key light is generally the brightest and tends to be quite soft in most portrait situations, but that doesn’t mean there isn’t a lot one can do with a hard key light. A key light is not necessary for all images.
A hair light will bring out edge detail in the hair and highlight its shape. Naturally, a hair light is often used when you want to separate your subject from the background. You can make your hair visible and bright, or subtle and barely detectable depending on how you photograph. It will look artificial and fake if it is visible. However, a subtler approach will result in a natural looking image. The image below uses a very soft and subtle hair light, so much so that it is barely even noticeable without looking for it specifically.
Hair lights are common spots or gridded/barn-doored lights as we don’t want any spill on the rest of the subject. A particularly significant problem with hair lights is that they can produce spill which can turn out as glare in your shot. This is why it is always a good idea to have a method of reducing that light spread to the area you actually need to cover: the subject’s hair. You can do this in several ways. One way is to place a grid over your light source and aim it at the subject’s hair. This will help reduce uneven light distribution. If however you only want to remove flare from your image, you can also place a flag between the light and your subject & camera. This way the light will be far more controlled, allowing less spill to occur which will eliminate glare.
Hair lights can add a lot of drama to the picture and are commonly used by Film directors in horror movies or intense scenes to amplify that feeling for the viewer. Add a dramatic key that produces dark shadows and you have a perfect setup for some dramatic images.
Fill lighting is used to reduce the contrast of your subject. You might want to add fill to enhance shadow details. You want fill to look as even as possible. It is a big light source that is placed behind your camera. Fill light should not cast any shadow at all. Fill light should not cast shadows. I have written a separate article on the subject.
The side-light is used for creating split setups. It is common for side-lighting to be dramatic as it reveals only one side of the subject’s face. Side-lighting with a strip softbox (Stripbox) is very common. Side-lighting can be achieved by placing your subject in front of a natural light source such as a window. Something to be cautious of and is considered a common pitfall with side lighting is not having enough fill light. It doesn’t matter how much fill you have, it is still important. When using side-lighting, aim for a minimum of shadow detail.
Kick lights are another way of highlighting the face (or whatever your subject matter is). Many people will often confuse a kick light with a hair light. The difference is that while a hair light will light up only hair, a kicker can do that, as well as light up a side of the subject’s face. This can create separation in the face and give definition. Kickers generally have a 0. 75 or 1 stop above the other lights hitting the face. You must balance your kicker correctly. It can be distracting if it is not done properly or inconsistency.
If you are using a kicker light, you should not forget that it is technically your key. It would make sense to use a large soft source for the fill light.
It is also possible to use a single light source to create both the kicker and fill lights with the right accessories. A large, bright source that is placed close to the subject’s face will provide the “kick”, while the larger size of the light will also help illuminate the rest. It is a good idea to place a reflector or foam core on the opposite side of your subject in order to make it easier.
Rim lighting is used to emphasize the subject’s shape and provide separation from the background. They are commonly strip boxes because of the thin and tall light pattern that they form. Rim lights are very common when photographing athletes and fitness professionals as they will accentuate the subject’s hard lines and body shape.
Remember that rim lights may also cause glare when placed incorrectly. If there is no way to avoid the light in your frame, you can add grids and flags to the strip softboxes to reduce that effect.
Another way to achieve rim lighting is by placing a small light source directly behind the subject. The light source will form a halo around subject’s head and body. You can even use one light to make rim or hair lights.
A catchlight is the little white spot often seen popping up inside the photo subject’s eye. The reason I put it on the same level of importance as the key or rim lights is simply that very few people pay attention to their catchlights. You can always see a bright spot in people’s eyes if you look closely at their real-world surroundings. A catchlight is essential for any event. Because catchlights reflect perfectly, it won’t take much to make them. An easy way to make catchlights is to place a small light source on the eye level of your subject and put it at a power setting where it would only show up in the eyes and pretty much nowhere else.
Remember, these “definitions” and suggestions are only a single way to approach lighting for portraits. The truth is there is no right or wrong way to light. There is only appropriate, and not appropriate for the image you are trying to create. The same applies for light functions. If the picture calls for it, use a hair light and nothing else. I am simply presenting common definitions of light as applied to portraiture, not the right way of doing light. Truth be told, there have been times when I broke a few rules but it was a good solution for my situation. It also created an interesting image.
Regardless, I hope these terms cleared up a little confusion and helped you figure out something new for your next portrait session.
Image credits: Header photo from Depositphotos