Hard and soft light

Learning goal

You will be able to name the quality of light by looking at the edge of a shadow and explain where this difference comes from: the softness of light is decided not by the real size of the source but by how big it looks from the subject. You will learn to soften light by bringing it closer, by spreading it with a curtain or a thin fabric, or by bouncing it off a wall; to use hardness on purpose in open sun or with a bare bulb; and you will be able to choose the quality of light deliberately in a portrait.

The question

Look at your shadow on the pavement on a sunny noon: its edges are sharp as if cut with a knife, dark and clear. On the same day, when the sky is covered with cloud, stand in the same spot again: your shadow has almost disappeared, and a soft, faint darkness is left around your feet. Neither you nor the pavement has changed. What has changed is the light itself.

Why are shadows sometimes sharp and sometimes soft? The answer is surprisingly simple: the size of the light source. A small source gives a hard shadow, a big source a soft shadow. But here "size" sets a trap, because the biggest light source in our sky is the sun, and it gives the hardest shadows. In this lesson we will resolve this contradiction and learn to sharpen and soften the edge of a shadow as you wish.

Context

In the previous lesson you saw how the direction of light rebuilds the shape of a face from scratch. Direction decides where the shadow will fall; quality decides how that shadow will look. Even if the direction stays the same, a sharp or a spread-out light tells the same face in a completely different way. Hard light tells of tension, energy, an open summer noon; soft light of calm, closeness, a cloudy morning. The question isn't which is better; it is which fits what the photo wants to say.

Understanding the quality of light gives the photographer one of the cheapest tools there is. The huge boxes, umbrellas and white boards put in front of studio lights all actually do the same job: making the light source bigger. You can do the same job at home with a net curtain, a white wall or by moving closer to a window. The physics of this lesson is the basis of every tool you will see later in studio lighting.

Simple explanation

What decides how hard light is?

The edge of a shadow is formed by the way light wraps around the subject. If the light source is very small, like a point, the light passing the edge of the subject stays as a single line and the shadow starts with a sharp edge. If the light source is big, light reaches around the subject from different angles; at the edge of the shadow a transition zone forms that is partly lit and partly dark. This transition band is called the penumbra, and the wider it is, the softer the shadow looks.

What matters here is not the real size of the source but how big it looks from the subject; we call this apparent size. The sun is a giant sphere, but it is so far away that in the sky it looks like a small disc only about half a degree across. That is why in open weather the sun behaves like one of the physically smallest sources and gives hard shadows. When clouds pass in front of the sun, however, the light spreads across the whole cloud layer and the entire sky turns into a giant light source; shadows soften and almost disappear.

How do you soften light?

Apparent size depends on both the size of the source and its distance, so to soften light you either make the source bigger or bring it closer. The easiest is bringing it closer. A window one meter wide, seen from one meter away, covers a wide area of about fifty degrees; from three meters away it drops to about nineteen degrees. Moving the person closer to the window both brightens and softens the light.

Passing light through a diffuser also makes the source bigger. When you draw a thin net curtain across a window the sun is hitting, the light strikes the curtain and spreads in every direction, and the light source is no longer the small sun but the whole curtain. Tracing paper, a white bedsheet or a thin fabric does the same job. Bouncing light gives the same result: when you turn a lamp or a flash not directly at the subject but at a white wall or the ceiling, the wide lit wall becomes a new, big light source. The logic behind all of them is one: making bigger the light source the subject sees.

Where the shadow falls also affects softness. The transition band of a shadow falling on the wall behind a person widens as the person moves away from the wall. With a source one meter across two meters away, the shadow of someone standing twenty centimeters from the wall ends with a transition of about ten centimeters; if the person moves one and a half meters away from the wall, this transition grows to about seventy-five centimeters and the shadow spreads out and disappears on the wall.

When do you choose hard and soft light?

Hard light isn't a light that has fallen out of favor. Sharp shadows bring out shapes, lines and texture strikingly; the roughness of a stone wall, the weave of a fabric, the wrinkles of an old hand reach their clearest in hard light. When you want a graphic, strong and energetic photo, hard light can be the right tool. On faces, on the other hand, it also enlarges every bump, every pore and every shadow line.

Soft light widens tonal transitions: a slow, stepless flow from light to shadow. That is why it is preferred in most portraits; it keeps the shape of the face without making it look coarse. Here it helps to know that skins behave differently. Hard light leaves sharp, small points of reflection on shiny skin or on dark skin; these points can draw the lines of the face, but if there are many of them they can also look like scattered glare. Soft light enlarges and softens these points; it brings out pink, warm transitions on light skin and deep, rich steps of tone on dark skin. You choose which suits the person by looking at what the face shows in that light.

Visual evidence

Picture two portraits of a coppersmith sitting by a window on a sunny afternoon. At first the window is bare; the sun is shining straight in. One half of the man's face is bright, the other half almost black. The shadow of his nose has fallen on his cheek as a sharp triangle, and each wrinkle is deep like a dark line. On his forehead and the tip of his nose there are small, white points of glare. On the wall behind him, the shadow of his head has drawn a silhouette as clear as if cut with a knife. A strong, hard face that shouts tiredness.

Then you draw a thin, white net curtain across the window and move the man a little closer to it. Now the light comes from the same direction but behaves completely differently. The lit half of the face darkens slowly toward the shadow with a soft curve. The shadow of the nose has become a faint darkness. The wrinkles are still there, but they are no longer cracks; they are fine lines on the map of the face. The points of glare on his forehead have widened into a soft sheen; the copper and coffee tones of his dark skin can be made out layer by layer. The shadow on the wall has spread out and almost disappeared. The same face, the same window, the same direction; the difference is made only by the size of the light source the subject sees.

Common mistakes

Summary

The sharpness of a shadow is decided by how big the light source looks from the subject: sources that look small, like the sun, give hard shadows, while sources that look big, like a cloudy sky or a big window nearby, give soft shadows. Bringing light closer, passing it through a curtain or bouncing it off a wall softens it; which quality you choose depends on what the photo wants to tell.

Mini assignment

In this assignment you change the hardness of light with your own hands.

1. Place an object or a volunteer's face next to a window the sun is shining straight through, and take a frame.
2. Stretch a thin curtain, a bedsheet or tracing paper across the window and take the same frame again.
3. Take two more frames with a desk lamp, first turned directly at the subject, then at a white wall nearby.
4. Compare the edges of the shadows in the four frames, and add a frame to your light journal in which the hardness of the light has changed.

Check yourself

• When you used a curtain or a wall, were you able to see the edge of the shadow soften?
• Were you able to set the hardness yourself by changing the apparent size of the light source?
• Were you able to say, with a reason, which of the hard and soft frames suited your subject better?

Glossary

Mini quiz

1. Why does the sun give hard shadows even though it is a giant source?

• A) Because its light is very bright
• B) Because it is so far away that it looks like a small disc in the sky
• C) Because its light is yellow
• D) Because it shines only at noon

2. Which of these should you not do to soften light?

• A) Move the source further from the subject
• B) Bring the source closer to the subject
• C) Pass the light through a thin curtain
• D) Bounce the light off a white wall

3. What happens to a person's shadow on the wall as they move away from the wall behind them?

• A) It gets sharper
• B) It doesn't change at all
• C) The transition band widens and the shadow softens
• D) It changes color

4. In which situation can hard light be a good choice?

• A) Never
• B) Only at night
• C) Only when you want to show a face as smooth
• D) When you want to bring out texture, line and energy

Answers

1. B — The hardness of light is decided not by real size but by apparent size; the sun looks only as big as a small disc about half a degree across in the sky.
2. A — A source that moves away looks smaller from the subject; the light both weakens and hardens. Bringing it closer, diffusing it and bouncing it make the source bigger.
3. C — The width of the penumbra grows with the size of the source and with the ratio of the distance to the surface the shadow falls on to the distance to the source; as the person moves away from the wall, the shadow spreads out.
4. D — Sharp shadows make the roughness of stone, the weave of fabric and the wrinkles of a hand their clearest; they give a graphic and energetic effect.

Summary card

• What decides hardness: how big the source looks from the subject.
• The sun looks small → hard; a cloudy sky looks big → soft.
• To soften: bring it closer, pass it through a curtain, bounce it off a wall.
• As the subject moves away from the wall, the shadow on the wall spreads out.
• Hard light tells texture and energy, soft light transition and closeness.

Bridge to the next lesson

You have got to know the direction and the hardness of light. At some times of day these two, and color too, come together in a way photographers love: the sun is low, light comes from the side, softens and warms. The next lesson asks about these hours: why does everyone shoot at sunset? There you will see how the golden hour and the blue hour change the light, and how to catch these hours.