How colour affects a photographs composition is complex. Our perception of colour is not only visual but stimulates an emotion depending on our experiences associated with that colour. Some are obvious and familiar to everyone e.g. red represents danger or heat, others may be more personal e.g. the colour of a loved grandmothers favourite flower.
Colours are also perceived differently depending on which other colours are within the same image.
The purpose of this exercise is to demonstrate how the strength of a colour is affected by exposure in a photograph. Each image is taken from exactly the same position and with the same lighting. The only difference between the images is that the camera settings have been adjusted to change the exposure. In this instance the increments are from 1 stop over exposed to 1 stop under exposed. The middle image has the average metered reading.
|1 stop over exposed|
|0.3 stop over exposed|
|Average exposure setting|
|0.3 stop under exposed|
|1 stop under exposed|
What has changed is how bright or light the colour appears. The more over exposed the image the lighter the colour and the more under exposed the darker the colour. The brightness also affects how saturated the colour appears. Underexposure gives a deeper saturation to the colour and vise versa.
The teaching manual goes on to ask which of the three colour qualities of hue, saturation and brilliance you can change at the time of shooting without moving the object or changing the light falling on it?
Well, if I understand the colour theory correctly, all three can be adjusted. Brilliance and how saturated a colour appears can be changed by altering the exposure of an image, whilst a colours hue can be altered by changing the white balance in camera on a digital camera or by using coloured filters on a film camera.