Afterimages

The reason for the phenomenon of increase in contrast with complementary colors is primarily not a characteristic of colors, but a characteristic of our eyes: The eye tends to enhance contrasts. The following experiment demonstrates this phenomenon: Just click on the link below, and a window revealing a red area opens up. You have to stare at this area for at least 30 seconds without moving your pupils.
If Javascript is activated, a white window will open automatically 30 seconds after having opened the red window - if not, please click on "open white window".
In this white window you have to concentrate on the little cross for a few seconds: Then, a turquoise-colored spot will appear as so-called "negative afterimage". The afterimage can still be seen when you close your eyes and cover them with your hands. The color of the afterimage will then be a little bit darker. By the way, this experiment works best in a darkened room:

This experiment would also work the other way round: After having stared at a turquoise-colored area, a red area would appear as negative afterimage. However, red is the complementary color of turquoise. Or to put it another way: The color that appears as negative afterimage is the complementary color of the original color! Science has not yet found out how exactly this enhancement of contrast comes about and why simultaneous contrasts appeal so well to the observer. So, this remains an issue of speculation.
 
We actually should find it strange: Could it possibly be that the symmetrical color wheel based on a physical rationale "is not correct"? When looking at the Symmetrical Color Wheel, we see: The complementary color of red is cyan! And not turquoise. Let's make another experiment, this time with yellow:

Here we can see that the afterimage is violet. This indicates that violet is the complementary color of yellow, although it should have been blue according to the color wheel. So, which color do we see when staring at magenta? Let's have a look:

The negative afterimage is green. So the complementary color of magenta is green. We now better have a little break so that the afterimage can dissolve, and then we will have a look at the complementary color of orange:

When looking at pure orange we see a cyan-colored afterimage. The complementary color of orange is cyan, and not a secondary color between cyan and blue, as indicated by the symmetrical color wheel.

"We can imagine that, on the contrary, the eye already expects the negative afterimage, so that the eye is able to automatically correct the distorted color impression. This would mean that the eye expects to see an area that is slightly outshined with violet (as negative afterimage) after having looked at a yellow area. And if we really look at a violet area after having stared at a yellow one, the eye would find its expectation confirmed. This might be the reason why we like it so much to see a yellow area next to a violet one."
(From: Roman Liedl, Die Pracht der Farben)

"Color is primarily not a physical, but a psychological phenomenon", the bauhaus teacher and painter Josef Albers once wrote. So you can rightly say:

"Observations are more important than rules."
Hans Gekeler

Next comes the color wheel according to Harald Küppers, also used by Roman Liedl:

 
Harald Küppers' color wheel

The precise names of the colors in Küppers' color wheel:

short name               precise name

yellow                   yellow
lime                     yellow green
green                    green
turquoise                blue green
cyan                     cyan blue
blue                     blue
violet                   blue violet
lilac                    red violet
magenta                  red magenta
red                      red
orange                   red orange
yolk                     yellow orange

On the symmetrical color wheel, blue is opposed to yellow:

But on Küpper's color wheel, violet and yellow are opposite each other. On the symmetrical color wheel, red is opposed to cyan; on Küppers's color wheel, however, red and turquoise are opposite each other!
Therefore you should not rely on the symmetrical color wheels, but on the one with color names when determining harmony contrasts according to Roman Liedl. This Harmonic Color Wheel can be reached via the Hot Start Page as well as via the help menu in the Color Selector. There you will find the corresponding colors next to the color names.
The Color Selector for Harmony Contrasts represents the most efficient way of determining a harmony contrast. This Color Selector has the advantage of being very clear and time-saving: The impression of an angular harmony can be judged immediately. By using the Color Selector, you do not need to set up a color combination on a web site only to get an impression of its effect. Working with the Color Selector shall also make you realize that colors can be used in a targeted way: either as 2-, 3-, 4-color harmony, as fannings or as color rows (these terms are explained in the chapters harmony theory and surface design).
 
These afterimages are indeed responsible for the fact that the effect of colored areas changes: If a web site contains disharmonic colors, it will become even more disharmonic in a short while: The afterimages appear against the background, and since they are complementary afterimages, they are disharmonic as well.

Just click on the link below, and you can compare all color wheels we have discussed so far in separate windows: