What is Basic characteristics of lighting?

Quality. The best way to describe the ‘quality’ of a light source is in terms of the type of shadow it makes objects cast. The shadows can be hard and clear-cut, soft and graduated or somewhere in between. As Figure 2.5 showed, this quality depends on the size of the source relative to its distance from your subject.

Hardest light comes from direct use of the most compact, point-like source, such as a spotlight or projector bulb, a small flashgun, a torch, a lighted match or direct light from the sun or moon. (The sun and moon are vast in size, but because of their immense distances they form relatively small, intense sources in our sky.) All these light sources vary enormously in intensity and color, but when used direct they all make sharp-edged shadows form.

The softest light comes from a large, enveloping source. This might be totally overcast sky or a large, frosted window. It could be a lamp or flashgun with a large-diameter matt white reflector, or a cluster of fluorescent tubes. You can make any hard light source give soft lighting by placing a large sheet of diffusing material, such as tracing paper, between it and the subject. The larger and closer your diffuser is to the subject, the softer the lighting.

Similarly, you can direct a hard source on to a large matt reflector such as a white-lined umbrella, card, or the ceiling or a nearby wall, and use only the light bounced from this for your subject illumination. The opposite conversion is also possible. You can make a large, soft light source give hard illumination by blocking it off with black card, leaving only a small hole. Indoors, if you almost close opaque window blinds you can produce fairly hard light even when the sky outside is overcast.

The way size and closeness of your light source alters lighting quality also changes the character of reflections from gloss-surfaced subjects. A hard light source gives a small, brilliant highlight. Typical of this is the little point of light (‘catchlight’) in the eyes of a portrait (see Figure 7.20). Remember that these highlights in glossy surfaces are essentially mirror reflections of the light itself and so take on the shape of the lamp. The highlight from a soft light reflects the large, diffuse source giving a paler, spread highlight, which may sometimes dilute the underlying colour of an entire glossy surface, making it look less rich.