You also have to consider the physiological effects of advancing and recessive colours. Warm colours appear to come forward and cool colour to go away from the plane they are on. A living room painted in cool blues or greens, for example, will appear to be more spacious and airy than one painted in warm reds or yellows. The walls seem to be further away. It doesn't take any great stretch of imagination to see why this situation is ingrained into the human instinct as it is evocative of the sky and the great outdoors.
Warm colours are 'cosy' and reminiscent of sitting round a fire.
A overly bright, warm background on a Web page makes for uncomfortable reading as the background seems to be in front of the text. Web designers should be aware of this 'palette' of optical illusion tricks. Where print designers have a wealth of type weights to play with, screen fonts allow very few. But, juxtaposition of hue and tone can simulate the effect of type weight to some extent. In environments of high tonal contrast, dark on light visually thins the type, whereas light on dark thickens it.