Three-point lighting for people who film themselves

Somebody has shown you the diagram. A head in the middle, three tidy circles around it, arrows pointing inwards. It is on every lighting page there is, it is correct, and it has persuaded a great many people that they need three lights before they are allowed to press record.

It is not a shopping list. It is a description of three jobs. One decides what your face looks like, one can be done by a white wall, and one can be left undone for a long time before anybody notices. Here is what each is for, and what you lose by dropping it.

What is each light for?

The key light

The key decides what your face looks like. Everything else in the setup is a reaction to it.

Its job is shape. A face needs a bright side and a shaded side, and the boundary between them tells a viewer that a nose is a nose. Where the key sits decides where that boundary falls, which is why it is the only one worth agonising over.

Placement has its own answers, set out in full in where to put your light when you only have one. Sort the key first: a well-placed key with nothing else in the room beats three lights arranged around a badly placed one.

The fill light

The fill sits on the other side of the camera from the key, roughly level with your face, and does exactly one thing: it decides how dark the shadow side of your face is allowed to go.

The fill controls shadow contrast. Adjust it against the key and the look you want, using the image and exposure tools; the same lamp output does not necessarily mean the same light reaches the face.

The back light

The back light sits behind you, out of frame and above head height, aimed at the back of your head. It draws a thin bright edge down the side of your hair and along one shoulder.

That edge is separation: it tells the eye where you stop and the room starts. It is also the most obviously professional-looking of the three, which is why it is the one people buy first and need least.

Which light can you skip for longest?

The back light, comfortably, and possibly forever.

Its job is separation, and separation has a free substitute: distance. Move your chair further from the wall and the wall receives much less of your key light, so it falls darker than you are and you separate by contrast, with no second light existing. A lamp already in the room, switched on behind you, does the same for nothing.

It earns its place under specific conditions: no room to move back, dark clothes against a dark wall, hair close in tone to the background. Then it holds the shot together. The rest of the time it is a light you dust.

What goes wrong when you drop the fill?

Something more irritating than it sounds.

Without added fill, the shadow side may be darker than you want. Check the recorded image: some rooms already return enough light, and a strong shadow can be an intentional choice. Add fill where it makes the subject easier to read.

The fill is the light that makes footage survive being watched in bad conditions, which is where most footage is watched. That makes it the second thing to sort and the back light the third, the reverse of most people's shopping order.

Can a wall do the fill light's job?

Yes. A nearby pale surface can return enough light for the fill you need.

Anything pale on your shadow side bounces some of your existing key light back into the shadow: a white wall, a sheet of foam board, a sheet over the back of a chair, a pale door left open. Move it nearer for more fill and further away for less, which is a finer control than most lamps give you. It is softer, too, because bounced light leaves a large surface rather than a small one, and large sources wrap around a face instead of cutting across it.

The limit is that a bounce needs a key with light to spare and a pale surface close to you. In a large dark room it does very little, which is where a second lamp stops being a reflex and becomes a real purchase.

Build it in this order

1. Position the key. 2. Check the subject against the background. 3. Try a pale surface for fill if the shadows need it. 4. Add a lamp where the existing light cannot do the job. 5. Consider a back light if it helps the separation or look.

The first three are free. Plenty of rooms never get past step three, and the videos are fine.

When is three the wrong number?

When the thing being taught is not your face.

Three-point lighting is written around a person talking, and assumes the person is the subject. If you are demonstrating something with your hands, the hands are the subject and the decisions change: whether you are shadowing your own work, whether the surface reads evenly, whether the viewer can see what you are pointing at. That puts a light where no diagram would draw one.

How many lamps to own follows from one thing: which single item in the frame the viewer must be able to see. Light that first, and the key, the fill and the back light become what they always were, three reactions to a decision made before anybody touched a lamp.

Sources and evidence

What here is established lighting physics, and what is our own order for building a one-room setup.

What is established. ARRI's own lighting handbook states plainly that the hardness or softness of a shadow is set by the physical size of the light source relative to the subject rather than by its brightness, which is why a diffused, closer or bounced light softens a face while a small hard source does not, however brightly it is run. The inverse-square law, formally defined by the CIE within its International Lighting Vocabulary, describes how a light's effect on a surface falls away with the square of the distance to it, which is why moving a subject further from a background wall lets the key light drop off sharply before it reaches that wall, separating the two by contrast without adding a light. Roger Deakins, a working cinematographer who publishes his own lighting forum, treats the three-light diagram as one way of solving these problems rather than the only correct one.

Our method. Building a setup key first, then chair distance from the wall, then a bounce, and only reaching for a second or third light once those are exhausted, is this studio's own order of operations, not a claim that the three-light diagram is wrong.

References.

• ARRI (Arnold & Richter Cine Technik); author Bill Holshevnikoff. ARRI Lighting Handbook, Fourth Edition. arri.com. Shadow hardness/softness is set by the physical size of the light source relative to the subject, not its brightness. Used in the two lighting pieces and the talking-to-camera piece. Text dates to 2016 (fourth edition); general lighting theory, not a claim about any specific fixture.
• International Commission on Illumination (CIE). 17-25-105 'photometric inverse square law', CIE S 017:2020 International Lighting Vocabulary (e-ILV). cie.co.at. Inverse-square falloff of light with distance; used to explain background separation and why a background darkens. Used in background-and-atmosphere-lights and the lighting pieces. Formal definition only, a special case of the wider photometric distance law; gives no production guidance itself.