The Angular Harmony

A color combination which is "outwardly neutral", in other words a Complementary Contrast, is described as an angular harmony by Roman Liedl. He distinguishes between 2-, 3-, 4-color harmony etc. (compare: Roman Liedl, Die Pracht der Farben, pp. 46 - 65):

 2-color harmony
 
Further 2-color harmonies: e.g. lime/lilac or orange/cyan.
 

 3-color harmony
 
Yellow is simply split up.Further 3-color harmonies: e.g. lime/magenta/violet or red/green/cyan.  

 3-color harmony
 
Further 3-color harmonies: e.g. lime/red/blue or orange/green/violet.

No 3-color harmony is red/turquoise/violet, because this combination is not outwardly neutral; red and turquoise are too far away from yellow to fulfill its function. When "splitting up", the maximum angular separation is little more than 120°.
 
However, the 3-color combination red/turquoise/violet offers an effect that should not be underestimated: The complementary contrast red/turquoise can be accentuated with violet and by this be loosened up a little bit. We can create a certain Tension, a small distance to what's regular, a niche for individuality. But we have to be very careful here to maintain the harmonic effect of the color combination. All angular harmonies on this page can be accentuated with a color that does not fit into the web site harmonically and therefore produces a "distorted" contrast. We just have to see to it that the accentuation merely creates a tension, and does not turn into a complete disharmony.
 

 4-color harmony
 
Yellow and violet have been split up.  

 4-color harmony
 
Further 4-color harmonies: e.g. yolk/orange/cyan/blue, red/turquoise/yellow/violet, orange/yolk/yellow/blue.  

 5-color harmony
 

 6-color harmony
 

These illustrations are just a few examples out of all possible combinations. Everybody can make their own combination; but you have to see to it that there is a "balance": To achieve this, you have to halve the color circle imaginarily; in the center of the one half we'll find our initial color, and exactly opposite it, in the center of the other half, we'll find its complementary color.
If you want to use only two colors, this complementary color is the result you have been looking for. To choose more than two colors, the complementary color has to be split up symmetrically, ie. to the left and to the right. Thus, you will obtain two new colors which each have the same angular separation from the original complementary color.
 
As experience shows, these 2- and 3-color harmonies are very effective on web sites. When using 4-color harmonies, you have to see to it that the angular separation does not get too big, because otherwise it would look too multicolored. 5-color harmonies etc. are more suitable for painting. This sentence should not be regarded as an irrefutable rule, but rather as a guideline for beginners. Again and again, there are exceptions to the rule: In some cases, 5-color harmonies etc. can be quite appropriate, if e.g., one color is used very extensively and the other colors are used extremely sparingly.
 
To give an "effect" to a monochromatic web site, it is sometimes quite sufficient to produce an emphasis by setting off one single color on a small area. It is characteristic for good design that colors are distributed sparingly, well-ordered and balanced in any respect.
 
If, for any reason, you should use 4-color harmonies etc., it would be best to divide the web site into elements and to put a simple angular harmony into every element. Here are some possible elements: logo, dividing line, buttons, frames, text fields, photos, graphics, animated GIFs and so forth.
If the web site has a specific focal point, you could increase its attraction by using an angular contrast.
 
In practice it may often occur that a given color combination is to be completed to become an angular harmony. If only one color is given, you just need to find its complementary color. If two colors are given, you could complement them to become a 3-color harmony. If a whole color row is given, e.g. from violet to orange, a single color could create a counterweight to this color row; in this case it is green. Sometimes we will not obtain a perfect angular harmony due to the fact that the color row is irregular. Nevertheless, this harmony will have a good effect, if the quantitative contrast, the colorful-uncolorful contrast and the light-dark contrast are arranged very well (these contrasts are described on the following pages). A more detailed description of the topic "given colors" can be found on the page Integration of the Associated Colors Into the Web Site.