essential skills: photographic lighting
intensity
Light intensity is a description of the level of a light’s brightness. The intensity of light falling
on a subject can be measured using a light meter. This is called an ‘incident reading’. A light
meter built into a camera does not directly measure the intensity oflight falling on the subject
but the level of light reflected from it. This is called a ‘reflected reading’.
Reflectance
Regardless of the intensity of the Light failing on the subject different levels of light will be
reflected from the subject. The amount of light reflecting from a surface is called ‘subject
reflectance’. The levels of reflectance vary according to the color, texture and angle of the light
tojthe subject. A white shirt will reflect more light than a black dress. A sheet of rusty metal will
reflect less light than a mirror. In all cases the level of reflectance is directly proportional.to the
viewpoint of the camera. If the viewpoint of the camera is equal to the angle of the light to the
subject the reflectance level will be greater. The level of reflected light is therefore determined
Reflectance of the subject.
- intensity of the light source.
- Angle of viewpoint and light to subject.
- Distance of the light source from the subject.
Although the intensity of the light source may remain constant (such as on a sunny day) the
level of reflected light may vary.