The direction of light

Learning goal

You will be able to describe in words how light changes a face when it comes from the front, the side, behind, above or below. You will show with examples that front light flattens, side light adds depth and texture, and backlight leaves either a dark shape or a thin line of light; you will know how to change the direction of light by turning yourself or your subject when you can't move the sun or the lamp, and begin choosing direction deliberately in a portrait.

The question

Sit facing a friend in a dark room and take a flashlight in your hand. First hold it straight at their face, at the level of their nose. Then slowly move it to the side, to the level of their ear. Next take it behind them, and finally lower it under their chin. The face is the same face, but in each position it looks like someone else: first flat and plain, then half dark and mysterious, then only a thin line of light, and finally the face of a ghost story told around a campfire.

How does the direction of light change a face? This was one of the questions we asked in the previous lesson to describe light: where does the light come from? In this lesson we will try that question out on a face. The short answer is this: light from the front flattens, light from the side deepens, and light from behind either darkens the subject into a shadow play or draws a line of light around it. Each direction makes the face say something different.

Context

What shows the shape of a face to our eye is the way light and shadow are spread over it. The shadow on one side of the nose tells how far it sticks out, the darkness under the cheekbone how the face is hollowed, the brightness of the forehead how round the head is. When light changes direction, this spread is rebuilt from scratch and the face takes on a completely different shape. That is why, for portrait photographers, the direction of light is as important as the subject itself.

The good news is that you don't have to move the light source to change the direction. You can't move the sun, and you can't carry the window; but you can turn yourself and your subject. Turning a friend slightly sideways to a window, putting the sun behind their shoulder on the street, or walking a few steps around them completely changes the direction from which light reaches the face. This lesson is here to show the big effect of these small movements.

Simple explanation

How do front and side light change a face?

When light comes straight from the front, from behind the camera, every part of the face is lit more or less evenly. The shadows fall behind the face and can't be seen from the camera. The result is a flat, plain and readable face. This front light softens wrinkles and roughness, suits document photos and surprises no one. But it also flattens the shape: the nose, chin and cheekbones stand out less, and the face can look like a sheet of paper. A person squinting when you put the sun right behind you is also a well-known price of front light.

When you move the light a little to the side, so that it makes roughly half a right angle with the face, the face suddenly gains volume. A small shadow falls on one side of the nose, the area under the cheekbone darkens slightly, the line of the jaw stands out. When you take the light further to the side, to the level of the ear, the face splits down the middle: one half bright, the other half dark. This sharp split creates a strong and mysterious mood, but it may not suit every portrait. Side light also brings out texture; it makes visible the pores of the skin, the hairs of a beard, the weave of a fabric.

What does light from behind do?

When light comes from behind the subject, toward the camera, it is called backlight, and the result depends on what you expose for. If you expose the photo for the bright sky behind, the subject turns into a dark shape, that is, a silhouette. The detail of the face disappears, and only the outline of a profile, of hair or of a hand gesture remains. A silhouette tells shape, not detail, and used well it is very powerful.

If you expose the photo for the face and can get a little light onto the face, for example with light reflected from a wall in front of them, something else happens this time: a thin, bright line of light appears at the edge of the subject's hair, shoulders and cheeks. This is called rim light. Rim light separates the subject from the background, as if drawing a frame of light around it. At the outer edge of dark hair or dark skin this bright line stands out especially clearly and makes the shape of the face readable even in front of a dark background.

Why do light from above and light from below need care?

Light coming straight from above, like the noon sun, falls on the raised parts of the face, the forehead and the top of the nose; it leaves the hollow parts, that is the eye sockets, the area under the nose and under the chin, in darkness. The eyes can turn into two dark hollows and the person looks tired. The darkness of the eye sockets can grow even deeper in the photo as the skin gets darker, and the eyes can almost disappear. In that case, moving the person into the shade of a tree or under an eave, or asking them to lift their chin a little, changes the direction of the light.

Light from below, on the other hand, almost never occurs in nature; daylight always comes from above. That is why lighting a face from below throws the shadows in a direction we aren't used to, upward, and creates a strange, eerie effect. The faces in horror stories told around a campfire look like this. But a soft version of this direction is also useful: gentle light from below, reflected from a white book on someone's lap or from a light-colored table, can fill in some of the dark shadows left by light from above.

Visual evidence

Imagine photographing a friend sitting on a stool in a dark room four times with a single desk lamp. First the lamp is right behind the camera. Your friend's face is evenly lit from top to bottom, with hardly any shadow; the face is flat, plain and a little like a familiar ID photo.

You move the lamp to the right at half a right angle. Now a small shadow has fallen on the left side of their nose, the cheekbone stands out, and a shaded triangle has formed on their left cheek. The face has deepened and gained volume like a sculpture. When you take the lamp behind your friend, a little above their head, most of the face sinks into darkness; but a thin, golden line of light appears at the edge of their hair, shoulders and ear and draws the whole silhouette against the dark background. Finally you lower the lamp under their chin: the shadows of their nose and eyebrows stretch upward toward the forehead, and the familiar face turns into an eerie mask in an instant. The same face, the same lamp; the only thing that changes is the direction the light comes from.

Common mistakes

Summary

The direction of light rebuilds the shape of a face from scratch: light from the front flattens and simplifies, light from the side adds depth and texture, light from behind draws either a silhouette or a bright edge that separates the subject from the background, and light from above and below needs care. When you can't move the light, turning yourself or your subject is the easiest way to choose the direction.

Mini assignment

In this assignment you try out the direction of light on a face.

1. In a room with the lights off, light a volunteer's face, or your own face in a mirror, with a single desk lamp.
2. Take four frames, holding the light from the front, from the side at half a right angle, from straight to the side and from behind.
3. Under each frame, write how the face changed, which area was lit and which stayed in shadow.
4. Go back to your light journal: photograph the object you chose once more at a time when the sun hits it from a different direction, and note the difference.

Check yourself

• Were you able to describe in words the difference the four directions left on the face?
• In backlight, did you see the difference between a silhouette and rim light?
• Did you add a frame to your light journal taken when the direction of light had changed?

Glossary

Mini quiz

1. How does light from the front affect a face?

• A) It lights the face evenly and flattens the shape
• B) It splits the face in two
• C) It turns the face completely into a silhouette
• D) It leaves the eye sockets in darkness

2. What happens when light comes straight from the side, from the level of the ear?

• A) The face is lit evenly everywhere
• B) A thin line of light appears around the face
• C) The face splits down the middle; one half is bright, the other dark
• D) The shadows fall upward, toward the forehead

3. What do you do to get rim light in backlight?

• A) Expose the photo for the sky behind
• B) Turn off the flash and never touch the screen
• C) Turn the person to face the sun directly
• D) Expose the photo for the face and get a little reflected light onto the face

4. Why do the eyes turn into two dark hollows in the noon sun?

• A) Because light comes straight from above and leaves the eye sockets in shadow
• B) Because light comes from below
• C) Because there is very little light
• D) Because the lens is dirty

Answers

1. A — Light coming from behind the camera lights every part of the face evenly, makes the shadows invisible and flattens raised areas such as the nose and chin.
2. C — Light from the level of the ear reaches only one half of the face; the other half stays in shadow and the face is split sharply down the middle.
3. D — Exposing for the sky gives a silhouette; exposing for the face and adding a little reflected light from the front leaves a bright line at the edge of the hair and shoulders.
4. A — Light from above falls on the forehead and the top of the nose; the hollow eye sockets stay in shadow and look like dark patches in the photo.

Summary card

• Front light: flat, plain, readable; flattens the shape.
• Side light: volume and texture; straight from the side it splits the face in two.
• Backlight: expose for the sky → silhouette; expose for the face → rim light.
• Overhead light: the eye sockets darken; move into shade or lift the chin.
• If you can't move the light, turn yourself or your subject.

Bridge to the next lesson

You have seen how the direction of light rebuilds a face from scratch. But even two lights coming from the same direction can leave very different shadows on a face: one sharp as if drawn with a knife, the other soft like a mist. The next lesson goes after this difference and asks why shadows are sometimes sharp and sometimes soft. There you will see how the size of the light source decides the edge of the shadow.