Colour illusions in Spot 09
Experimental procedure for Spot 09
Colour illusions with different degrees of scaling
Bezold effect versus assimilation effect
When playing with this spot, you can see for yourself that many shades of colour that are produced by coarse scaling with the Bezold effect are not present with fine scaling with the assimilation effect, and vice versa. If you successively increase your distance from the picture when observing the Bezold effect, the illusion automatically changes into the assimilation effect. If you increase he distance with a finely scaled picture, you soon go beyond the critical distance at which the slatted structure vanishes completely. The lights from the various colour elements then overlap one another on the retina. When this happens, we talk of an optical or proportionate colour mix . Good examples of this are to be found on the colourful wings of butterflies, which are transformed under the microscope into structured entities with tegulae in a variety of colours.