Without light, there is only pitch blackness – and visual art is impossible! We see a head, or any object, only because it is hit by light. The resulting pattern of light and shadow gives us a sense of a head’s plastic, three-dimensional form, so it is very important to consider the direction, quality and strength of the light source. Subjects in real life are often affected by multiple, complex light sources, but the simplest lighting is to use a single source, such as a lamp or sunlight. (Natural light is changeable, so if you like your light constant and under your control, keep it human-made and keep it indoors.)
Direction of light
Changing the direction of the light source produces different effects upon the head. Let’s look at the main options.
Front lighting
The light is directed straight into the subject’s face. This is the simplest form of lighting, but when the head is seen straight on it can look flat because of the thin shadows and lack of contrast.
Back lighting
The light is directed straight at the back of the subject’s head, creating a halo-like bright edge and throwing the face into dark shadow. This makes the features hard to see, so it’s poorly suited to normal portraiture.
Side lighting
In these two illustrations the light is directed to the left- and to right-hand side of the head. This approach tends to split the head into contrasting light and dark halves. This is too dramatic for most portraits, as the features in the dark half are obscured, but an artist may like the effect for some pictures. You can vary the tones inside the light and dark halves without compromising the boldness of the pattern.
Back and side lighting
The light is directed from behind the subject but from the side, not directly behind. In this example, the light is from the back left. Creates a relatively small light area and throws the face into shadow.
Lighting from below
The light is directed up towards the head from below (underlighting). The effect is highly dramatic, and it distorts the features, making it popular for horror or melodrama. A light source from below is rare in nature – the effect could be caused by a fire or a laptop monitor.
Lighting from above
The light is directed down towards the head, creating dark shadows under the eyebrows, nose and chin. You might see an effect a bit like this outdoors when a bright sun is directly overhead.
Lighting from above and to the side
The light source here is directed slightly to the side and slightly from above. This is the most common lighting used in portraiture, as it has a balance of lights and darks that nicely reveal the forms of the face without distorting or confusing the features.
(I’ve put these illustrations together as a single sheet here.)
Studio lighting
In the illustrations above, we talk about one main light source. But there is light inside the shadow areas too thanks to other, weaker light sources. In fact, the industry standard for lighting a subject in a studio, known as ‘three-point lighting’, uses three main light sources: main (or key) light, fill light and back light. The purpose is to place the lights around the subject to illuminate it most effectively:
The key light is the main source that shines directly on the subject. It’s commonly set up at an angle to the subject to avoid the flattening effect of straight-on light, and is usually the hardest, brightest light of the setup. If you’re outdoors, it might be the sun; if indoors, it could be a studio spotlight.
The key light casts shadows, so from the other direction we use a fill light. This tends to be weaker or softer than the key light and evens up the overall distribution of light by making the shadow areas less intense. The fill light can be provided by a lamp, but artists often prefer to use reflected light, such as a card or curtain that bounces light back onto the subject more subtly than a lamp. Adding fill light brings the scene closer to the diffuse light of the outdoors and so helps make a picture look more natural; a weak fill light will make the key light more dramatic.
The back light (also known as edge light or rim light) is optional. Shone from behind, it creates a bright outline along the edge of the subject, either straight on or to one side, separating him or her from the background. This should be subtle, so it doesn’t disturb the other two light sources or the range of tones that clarify the forms. It can be effective to use a different colour to the main light: for example if the main light is warm, e.g. yellowish or orange, then the back light could be cool, e.g. blue. If you only use back light, the result is a mysterious-looking subject, seen in silhouette.
I’m not asking painters to become photographers. But we need to understand how lighting works, especially when painting a head from imagination, because light is so important to achieving a sense of realism.
Tips
- People tend to focus on the most brightly-lit part of a scene.
- Similarly, too much light in unimportant parts of a picture can be distracting.
- To create drama, use a strong light that throws dark shadows.
- To flatter your subject, use a soft light that doesn’t expose their flaws.
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