Catchlight

A catchlight is the small bright reflection of a light source that shows in the eye of a person or animal in a photograph. It matters because people read a face through its eyes, and that one bright point is what makes an eye look wet, rounded and alive instead of like a flat dark disc.

It is also the most honest record of the lighting in any portrait. The eye is a tiny curved mirror, so the catchlight shows you how many lights there were, roughly how big they were, and where they stood. Once you know the simple rule behind where it lands, you can put it where you want before you press the shutter, and read it in other people’s photos afterward.

What a catchlight actually is

The front of the eye is covered by the cornea, a clear, wet, dome-shaped surface. Like any smooth, shiny surface it reflects part of the light that hits it, and because it is curved it works as a small convex mirror, the same kind of mirror as the back of a spoon. The catchlight is the image of a light source in that mirror. It is a specular highlight, the same thing as the bright glint on a glass bottle or a polished car.

Three things follow from that, and they clear up most of the confusion about catchlights:

• A catchlight is not something extra you add. Every bright thing in front of the subject that the eye can mirror toward the lens makes one: a softbox, a window, the open sky, a white wall, even a bright shirt on the photographer. Choosing your catchlight means choosing and placing the light itself.
• It sits on the surface of the eye, not inside it. That is why it shows over the iris and pupil alike, and why, when the eye looks around, the catchlight moves much less than the iris does and seems to slide across it. Red eye is a different effect: flash light going into the eye through the pupil and bouncing back from the back of the eye, where the blood-rich layer behind the retina turns it red. The green or gold eyeshine of animals at night is the same kind of inside reflection, from a reflective layer behind their retina.
• It is a mirror image, not a glow. The cornea reflects only a few percent of the light that reaches it (about 2.5 percent head-on), so the catchlight is only as bright as the surface of the source it mirrors. The sun makes a blazing point, a lit softbox a bright patch, a grey sky a faint sheen.

Where the catchlight lands: the half-angle rule

A mirror reflects light toward the camera only at the spot where its surface faces halfway between the light and the lens. On a ball-shaped cornea that spot moves round the curve as the light moves, but only half as far. Put a light 45 degrees to one side of the lens, as seen from the subject, and the catchlight sits about 22.5 degrees round the cornea from its center, on the same side as the light.

Using typical eye measurements (a cornea curved like a ball about 7.8 mm in radius, and an iris about 11.7 mm across), here is how far from the center of the iris the catchlight sits for lights at different angles from the lens axis. The same numbers work up and down as well as side to side.

Four practical rules come out of that table:

• Same side. A light at camera left puts the catchlight on the left side of each eye as you look at the photo. A light above the camera puts it near the top.
• Half the movement. Swinging a light a long way round the subject moves the catchlight only a little. That is why a key light 45 degrees up and to the side still lands comfortably inside the iris.
• The side light still shows. A light at 90 degrees, which lights only half the face, still puts a catchlight in the near eye, close to the edge of the iris. The far eye usually gets none, because the nose blocks the light.
• Light from behind never shows. A rim light or the sun behind the subject can outline the hair and still leave the eyes with no catchlight at all.

Reading the eye like a clock face

Photographers describe catchlight position as a time on a clock face drawn over the iris, as you see it in the photo. Because the catchlight always moves toward the light, each of the classic portrait lighting patterns leaves its own mark in the eyes.

• On-axis flash or a ring light: a point or a ring right over the pupil. Ring lights leave a ring with a dark middle, where the lens sat inside the ring.
• Butterfly (Paramount) light: the light is straight in front and well above, so the catchlight sits at 12 o’clock.
• Loop and Rembrandt lighting: the light is up and to one side, so the catchlight sits around 10 to 11 o’clock, or 1 to 2 o’clock if the light is at camera right. Rembrandt pushes the light further round, so the mark drifts further out.
• Split light: at the edge of the iris, at 9 or 3 o’clock, and usually in one eye only.
• Clamshell: a key light above and a reflector or second light below gives a bright catchlight high in the eye and a dimmer one low. The lower one reads as natural only while it stays clearly weaker than the top one.

Want the face shadows that go with each of these catchlight positions? Portrait lighting patterns shows where the nose and cheek shadows fall for butterfly, loop, Rembrandt and split light.

The same reading works backward. Count the marks to count the lights. Check which side and how high they sit to place each light. Look at their shape for the modifier. Then compare both eyes: the two catchlights normally sit in about the same place in each eye. A clear difference usually means the light was very close, so each eye saw it from a slightly different angle, or the nose or brow blocked part of it from one eye.

Size, shape and brightness

Size depends on apparent size, not real size

The cornea makes a tiny image of whatever it mirrors, and the size of that image depends on how big the light looks from the subject’s position: its width compared with its distance. Worked through with the same eye measurements, a 90 cm softbox 1.5 m from the face covers about 33 degrees of the subject’s view and makes a catchlight roughly a fifth as wide as the iris. Move the same box back to 3 m and the catchlight shrinks to about a tenth of the iris. Twice the distance gives roughly half the width.

The sun is the extreme case. It is enormous, but it covers only about half a degree of the sky, so its catchlight is a pinpoint a few hundredths of a millimeter across on the real eye. A whole overcast sky is the opposite: so big that it can fill the top half of the eye with a broad, soft reflection, often with the horizon cutting across it. This is the same idea as hard versus soft light, which also depends on how big the source looks from the subject, so a big catchlight and soft shadows usually come together.

Shape is the shape of the light

A softbox makes a rectangle or square, an octagonal box an octagon, an umbrella a round patch, often with the ribs showing. A beauty dish makes a round catchlight with a dark spot in the middle, where its center plate blocks the bulb. A ring light makes a ring. A window makes a rectangle, often crossed by the dark lines of its frame, and outdoors the eye usually mirrors a whole scene in miniature: bright sky above, a darker band of trees or buildings below, sometimes the photographer.

No shape is correct, and claims that round catchlights feel warmer or square ones colder are taste, not rules. What does matter is consistency: in a set of portraits shot together, matching catchlights make the set look planned.

Brightness follows the surface brightness of the source

Because the cornea reflects only a few percent of the light, a catchlight is bright only when the surface it mirrors is bright. A small, intense source, such as bare flash or the sun, makes a small catchlight that is pure white. A big, dim source, such as a grey sky or a large softbox turned well down, makes a big one that can be pale and faint. The catchlight also shows best against something dark, so it stands out most over the pupil and over dark irises, and least over pale ones.

Want to know why the same catchlight turns hard or soft with distance? The inverse square law covers how light changes as you move it, and light modifiers covers the shapes you can put in front of it.

Why an eye shows no catchlight

When the eyes come out flat and dark, one of these is almost always the reason:

• The light is behind or too far to the side. Past about 100 degrees off the lens axis, the cornea cannot mirror it toward you.
• Something shades the eyes. A hat brim, a heavy brow, deep-set eyes or overhead midday sun leave the eye sockets in shadow with nothing bright in front of them to reflect.
• The subject looks down. Tilting the head down turns the cornea away from the sky or the light.
• Nothing in front is bright. In open shade with a dark wall or a dense hedge facing the subject, the eye mirrors darkness.

A missing catchlight is not always a mistake. Film and portrait photographers sometimes keep light out of the eyes on purpose to make a face harder to read, cold or menacing, and backlit portraits often go without them. The point is to choose it rather than discover it later.

Getting catchlights with the light you have

Window and daylight

Turn the subject toward the window, or put the window just to one side of you, and have them lift their chin a little. Standing close to the window makes the catchlight bigger. Outdoors, open shade works because the subject stands out of the sun but faces a large patch of bright open sky, which becomes a big, soft catchlight. On an overcast day the whole sky does the same job; face the subject toward its brightest part. In direct sun the catchlight is a hard pinpoint, and the subject will often squint, so shade usually wins. Low golden hour sun in front of the subject puts the catchlight near the middle height of the eye rather than high, and gives it a warm color.

Reflectors, walls and the photographer

A reflector held low and in front bounces light up into the eyes and adds the lower catchlight of a clamshell setup. A white wall, a pale building or sunlit pavement can do the same job. Held higher, a reflector can be the main catchlight when the sun is behind the subject. Remember that the photographer is also in front of the subject: a white shirt adds a faint extra reflection, and a dark jacket helps keep one out.

Flash and studio light

Bare on-camera flash puts a hard point right over the pupil, which looks flat and can blend into the pupil. Bounced flash off a ceiling just in front of the subject, or a wall to one side, makes a bigger, higher catchlight. In the studio, raise the key light until the catchlight sits in the top third of the iris, and if a fill light adds a second mark that distracts, move the fill, turn it down, or replace it with a reflector placed where its reflection is not visible from the camera.

Before you move any stands, it can help to sketch the setup. The lighting setup diagram tool lets you place the camera, subject and lights from above, the same view as the first diagram on this page, so you can see which side and how far round each catchlight will land.

Animals, groups and glasses

Animal eyes follow the same rule, and in wildlife photography a catchlight is often what separates a keeper from a near miss. You cannot move the light, so you wait for the animal to lift its head toward the sky or turn toward the sun. Dark-eyed animals in particular need one, or the eye disappears into dark fur or feathers.

In a group, everyone needs to see the same bright source, so use one that is broad and high: a big window, a large softbox or a wide patch of sky. A small light leaves the people at the ends with weaker catchlights or none. With glasses, the lenses are mirrors too, and they send light off at the same angle it arrives. Raise the light, or tilt the frames down slightly by lifting the arms off the ears, so the reflection off the glass misses the lens while the light still reaches the eyes. Glasses glare in photos goes through the fixes in detail.

Catchlights in editing

A catchlight that is there but dull can be brightened a little with a small, soft brush in a local adjustment or with dodge and burn. Work at low strength and treat both eyes the same, because one sparkling eye next to one plain one looks odd at once. You can also remove distractions inside the catchlight, such as your own silhouette or a light stand reflected in the eye, as part of normal photo retouching.

Painting a catchlight into an eye that had none rarely convinces. A real catchlight matches every other clue in the photo: the shadows, the reflections on skin, the second eye. A painted one usually disagrees with at least one of them. If the eyes came out dead, the reliable fix is to shoot again with the light moved.

Need the eyes to be sharp before the catchlight even matters? Eye detection autofocus explains how the camera finds and tracks the nearest eye.

Common mistakes with catchlights

• Looking for the catchlight on the wrong side. It sits on the same side as the light, not the opposite side. If it is on the left of the eye in the photo, the light was at camera left.
• Thinking a bigger light always means a bigger catchlight. Distance matters as much as size. A huge source far away, like the sun, makes the smallest catchlight of all.
• Assuming dark eyes cannot show them. A catchlight stands out most against dark irises and the pupil. Pale eyes are the ones where it can get lost.
• Treating 10 or 2 o’clock as the only right answer. Twelve o’clock, the center and the iris edge are all normal for their lighting patterns. What usually looks wrong is a single catchlight low in the eye, from light that comes only from below.
• Letting a fill light add a confusing second catchlight. Two or three marks of different shapes in each eye make the light look accidental. Move or soften the fill until its reflection disappears or is clearly secondary.
• Checking only in editing. On the back of a camera screen the catchlight is easy to miss. Zoom in on one eye of the first frame of every setup.
• Painting catchlights in afterward. They seldom match the light in the rest of the photo.

Try this: map a light with a practice eye

You need a small shiny ball (a marble, a glass ornament or a metal ball bearing), a window or a lamp, and a camera or phone. Ten minutes is plenty.

1. Set the ball on a table, about a meter from a window, with the window to one side of you. Photograph it from about 30 cm, filling the frame. This is your eye.
2. Take four pictures, moving yourself round the ball so the window is roughly straight behind you, then 45 degrees to one side, then 90 degrees, then behind the ball. Keep the ball in the same spot.
3. Now a person, if one will sit for you: have them face the window, then turn their head in four steps away from it, taking one photo at each step.
4. Zoom in on every frame. In each one, mark where the bright reflection of the window sits and how big it is.

Judge it this way. The reflection should stay on the window’s side of the ball and creep toward the edge as the window moves round, moving about half as far as you did. It should be gone when the window is behind the ball. In the portraits, find the head angle where the window still lands in the upper part of both irises: that is the angle to use next time you shoot by a window. If the reflection seemed to move to the side away from the window, check the frames again: it never does.

Want to see what other kinds of light do to a face? Natural light photography covers window, shade, sky and sun as light sources in their own right.

Catchlight questions

Where should a catchlight be in the eye?

Most portraits look natural with the catchlight in the upper half of the iris, anywhere from 10 to 2 o’clock, because that matches light from above. Twelve o’clock, the center and the iris edge are all fine for butterfly, on-camera and split light. A lone catchlight low in the eye is the one position that usually looks strange.

How many catchlights should there be?

One per eye is the simplest and usually the cleanest, and a bright high one with a weaker low one from a reflector also reads well. More than that is a choice, not an error, but each extra light should earn its mark. If you cannot say which light made a reflection, it is probably a distraction.

Why does my subject have catchlights in one eye only?

The light is far enough to the side that the nose, brow or a turned head blocks it from the far eye. Bring the light a little closer to the camera, or turn the face a little toward it, until both eyes see it. In split light the single catchlight is normal.

Can I get catchlights with a phone?

Yes. A catchlight comes from the light and the angle, not from the camera. Put your subject facing a window or open sky, step so the bright area is behind or beside you, and check the eyes on the screen with a two finger zoom before you shoot.

Is a catchlight the same as red eye?

No. A catchlight is a reflection off the outer surface of the eye. Red eye is flash light going into the eye and reflecting off the retina at the back, which happens when the flash sits close to the lens in dim light.

Do animals need catchlights too?

For most animal portraits, yes, and dark-eyed animals most of all, because without a catchlight the eye can vanish into the fur or feathers around it. Wildlife photographers often wait for the moment the animal turns its head toward the sky or the sun to get one.