About assimilating simultaneous contrast

Colour appearance is affected by context. Small coloured objects will be more difficult to identify than larger coloured areas. Thus, you will be able to distinguish fewer colours with small point symbols or thin lines. Different surroundings also change the appearance of a colour. Small colour areas tend to appear more similar to their surroundings because of a perceptual process called assimilation. Conversely, contrast between a larger patch of colour and its surrounding colour will enhance the difference between them in a process called simultaneous contrast.

Stumbling upon a somehow uncommon sudden twin-body appearance, Sam Renseiw remembered bits of school wisdom about the Bezold-Brücke shift; Speculating for a moment about optical phenomenon, the Purkinje effect seemed to be the most adequate explanation to the visualisation above. View it here or go red above (patafilm #171, 01'33'', 3.5 MB, mov/quicktime-Flash here)

A certainly more mature approach is Brut Smog's mesmerising video Fleshtones. Triple X-rated downloads transformed into something of beauty, harmony and contemplation.