Subtractive lighting
Written by: Nate Torres
Last updated: July 30, 2024
Shadows and silence - dive into the artistry of subtractive lighting...
What is subtractive lighting?
At its core, subtractive lighting is the act of removing light. Essentially, creating shadows to produce a more dimensional image. Too much light on your image would poorly affect it, most likely making it look flat.
As responsible photographers, we should make our photos look three-dimensional, although they may be in two-dimensional media. This means we need to create shadows, even when there are none.
There are times when you want your image to fit a certain mood, either heartwarming, dramatic, serious, friendly, calm, etc. To properly create this mood, photographers need contrast to create deep shadows in their images. You can create these situations using natural light, but a studio will do a better job at this. Studios will ensure your contrast is sufficient for your needs.
What is the purpose of subtractive lighting?
The purpose already lies in the subtractive lighting definition to create great shadows, reduce the light to a more proper size, or prevent light from shining on a particular area.
Let’s say that you already have the perfect light for your catchlights in the eye, but as a consequence, your subject’s face becomes flat. This means either your light source lacks direction, is too large, or is both. This is when photographers use their tools or surroundings to create shadows. The light-blocking tool will be placed around the area where the shadow should be seen.
The shadow will improve your final image and make it more three-dimensional. Depending on the situation, you’ll probably need different tools, too. A black-colored device can block light from a light source.
Unfortunately, it tends to suck the light from its surrounding areas. On the other hand, white-colored devices can bounce the light around your subject, transforming the lighting around them. Photographers tend to use light reflectors on areas that already reflect light, such as light-colored concrete, buildings, or inside a white interior.
The act of reducing the lighting and adding shadows to your subject will also create a different ambiance. Depending on the amount of light blocked, your subject can look like “someone resting under a tree on a sunny day” to someone standing under the sun at noon.
It changes people’s perception of the image and also the image’s whole meaning.
How to use subtractive lighting?
Let’s start with the basic decisions that surround subtractive lighting. Photographers will often ask you to, first of all, search for a main source of light and a fitting background based on that light.
Sadly, this strategy will only work if you shoot at the perfect time of day with the ideal light. For the other photographers, they will usually start from an optimal background and then optimally use the available lighting.
The method above gives you much more flexibility if you decide to change the lighting on your subject rather than the other way around. With the background and its lighting secured, it’s time to decide to either add or subtract the light sources. In some rare situations, you may need to utilize both, but it will commonly become a straightforward decision.
If the background lighting is more intense than your subject, consider adding light sources. On the other hand, if the lighting in the background and subject is the same, consider subtracting the light.
One of the easiest ways to learn subtractive lighting is by practicing. Gradually start from a subject with the available light and slowly observe the changes as you add or subtract the light. Maybe use a white-colored object to fill the unflattering shadows around the eyes, jaws, and nose. Another source of light was added to add a flattering catchlight to the subject’s eyes.
Observe and try to fix areas you can improve; maybe some shadows could help define your subject features while making the image more dramatic. You can use your gobo to create an area that transitions from the highlights to the shadows. Such techniques are able to make the subject’s face more noticeable while also making them appear thinner.
Depending on your understanding of lighting and portrait, the changes you can make are almost limitless. Keep transforming your image until it looks more interesting and matches the likings of the client and yourself.
What to use for subtractive lighting?
The most common tools used for blocking unwanted lighting are gobos; some people also call them flags. Although these terms have existed for a long time, people rarely use these tools today.
The flag is black, opaque, flat, and can typically be held by your hand or mount. Most of the time, people will always use this flag in locations that are too open and produce flat lighting. Don’t have a flag? Then, use your surroundings instead! Similar results can be achieved by using a smaller yet natural light blocker, such as a tree.
The generic term of gobo itself is “go-between,” which, as you know, can be anything that goes between your subject and light. Your gobo can be the man-made architecture that is available around your location, too!
Gobos can start from buildings, houses, porches, trees, hedges, and pretty much anything that fits in the term gobo. If it blocks light, it’s technically a gobo, even if it's just your hand.
Each gobo has its own advantages and disadvantages. Trees can help you block the light while looking good in the picture.
Photographing outside your studio can be quite a hassle, with all the light coming from multiple directions and reflected by various objects. Subjects in the open will most likely have strong lights coming from both sides of the face. The photography industry refers to this as flat light, which looks pretty bland.
This flat lighting can be counteracted by using the previously mentioned flag. These light yet large flags/gobos can easily block light that would otherwise create flat lighting on your subject. The blocked light will then create a flattering three-dimensional aspect of your image.
You can block the natural light from wherever you want, some situations will require you to block the backlight, or maybe some light that would otherwise reflect on their face.
When to use subtractive lighting
Optimally, you would use subtractive lighting when your image looks rather flat. You are then given the artistic opportunity to either subtract the light on the background or face.
If you decide to use the gobo on the background, you will separate the subject from the background. Making it look more three-dimensional.
However, if you choose to subtract the light on the face, you will have a short lighting effect. You can recreate short lighting by positioning the face of the subject (which is covered by the gobo) closer to the camera.
Photographers will often use the natural type of gobo since they can also incorporate it into the picture. Maybe use a canopy or tree, as long as it doesn’t fully block your main source of light and eliminates the background bokeh.
Bokeh can be a smart tool to separate your subject from the background further, further emphasizing them as the center of attention. This method would most likely be your approach to individual portraits.
On the other hand, there are also group portraits. They are probably the most difficult to do, but they are always worth the effort. Since small trees and flags cannot block light for large groups of people, you’ll need to put more effort into scouting your location. Keep your eyes peeled for large trees, buildings, or hedges. They can potentially serve as the gobo and help add a three-dimensional effect.
You may need your group to be a bit closer to the gobo; why? Because you need to see how effective the shadows are on your subject's face. Some photographers will encounter difficulties looking for this subtle difference with their naked eye.
I suggest using a light meter to measure the highlights on the subjects' faces and taking a test photo afterward. Light meters will make the highlights and shadows pretty obvious if compared to when viewing the camera’s rear screen. Check the shadows and how effective they are. But which subject should you measure with a light meter?
Well, perhaps the subject closest to the gobo is between 20 and 10 feet, depending on the size of your gobo. Oh, for a little side note. Please don’t stress too much if you ca unable find the best location possible for your subtractive lighting; you’ll never always find it.
It is perfectly okay to use the softer kind of flat lighting when making a group portrait. But make sure to check the other elements.
Keep your groups in the shade and let the main source of light shine on your background. Using purely natural light with a little tampering and a subtractive light technique will result in flattering portraits.
They will look absolutely more natural than most flash techniques. In addition, you can save money since you don't need to purchase additional equipment such as Speedlights, soft-boxes, etc. Instead, you can save your money on a high-quality portrait lens. Isn’t that just nice?
In conclusion, subtractive lighting is basically adding shadows using objects that block the light between the light source and your subject. There are many options available to you, depending on your knowledge of lighting and portrait photography.
Photographers mostly use subtractive lighting to salvage images at locations that are too bright or flat. The shadows add definition, hide non-essential features, make your subject’s face thinner, and, depending on how you use them, add a sense of drama. The easiest way to get used to it is to learn and observe the changes that occur while fiddling with the light using your “gobo.” Good luck, and have fun!