The basic principles of lighting

Any drawing or painting is simply a recreation of light and shade. A good reference photograph for a drawing or painting therefore needs to be correctly lit.When working from a photograph, lighting is one of the few aspects an artist cannot change. An artist can only recreate what they see. They have no special knowledge that allows them to know information that has not been recorded by the camera.

The basic principles of lighting

Any photograph is merely a record of light falling on, and reflecting from an object. Differences in the levels of reflected light tell us about the shape of the object.

With faces, we normally expect to see a shadow under the nose to describe its size and contour, shadows around the eye sockets to convey their depth, highlights on cheekbones, etc. The roundness revealed by lighting is known as "modelling", and the level of modelling is determined by the direction and intensity of light falling on the subject.

How the direction of light affects a subject's appearance

When the direction of the main light source is on or near the subject/camera axis, a face will lack modelling and appear flat.

When the subject is front lit there will, for example, be scarcely any nose shadows, and the eye sockets will be as light as the cheeks.

Virtually the same effect is seen when the subject is lit mainly from behind. The whole face will be in the shade, and none of the features well defined.

Light falling anywhere in between these two extremes will create differing degrees of modelling, dependant on the angle and intensity of the light.

Where is the main light source?

When taking any photograph, the first concern must always be to establish the source of the light. It is very easy to do! When outside, we simply look to see where the sun is. When inside, the light will usually come in from outside through a window or doorway.

The second concern must be to establish the direction of the light, relative to the subject. The situation to most avoid is where the direction of the light is on or near to the axis of the camera (i.e. either directly in front of or behind the subject).

Altering the direction of the light

With portraiture, the best modelling is achieved when the light source is at an angle of between 30° and 45° above the subject, and between 30° and 45° to the left or right of the subject.

Larger angles should be avoided because they can overstress modelling and so exaggerate features.

When using natural daylight, the right overhead lighting can be easily achieved by avoiding particular times of day. Don't take photographs at midday when the sun is directly overhead (even on a cloudy day, the light will still be directional). The morning and afternoon are generally the best times.

To get the light to fall on the subject from the left or right, simply reposition them relative to the axis of the light source.

Intensity of the light

The third concern when addressing the issue of lighting is the strength of the light. The wrong strength of light can produce and amplify all the problems described. Both strong and low light levels can eliminate modelling.

Some solutions to poor lighting are outside of the scope of this article (and covered in "available light portraiture" and "bouncing flash"), but briefly, choosing the right time of day, as described above, is the easiest means of avoiding day-to-day poor lighting intensity problems.

Summary

Your photographs (and artwork produced using them) can be improved measurably, if - before you even pickup a camera - you take the following three steps.

Check to see where is the light coming from, and if it is falling within 30° to 45° above the subject.
Position the subject so that the light falls within 30° to 45° to the left or right of their face.
Do not take photographs if the intensity of the light is too bright or too dim.

Footnote: There are circumstances when these "rules" may be broken, but the intention of this article is to convey simple guidelines applicable to most situations.