Lately I’ve been studying signs of all types, notably traffic signs. I noticed that German traffic signs use only basic color combinations of a handful of colors. The picture below shows the three most common color combinations. I estimate that about 70 percent of functional signs in Germany use these colors. The shown signs display information about hydrants, and the gas- and water network.
Red shapes and black text are displayed on a white background, black content on a yellow background, and white content on a blue background. The alternative color combinations blue and black, and yellow and white don’t work because of their low contrast. On traffic signs these colors tend to be used for specific purposes, red to indicate danger, yellow for warnings, and blue for neutral indications.
One can only speculate why other high-contrast colors combinations such as green-white, orange-black, and purple-white are seldomly used. My theory is that it is because these three colors were traditionally taught to be the primary colors for subtractive color mixing. The picture below showns the color mixing circle developed by Bauhaus teacher Johannes Itten (picture source: Wikimedia). In todays printing process the colors cyan, magenta, and yellow are used to mix colors.
In art history the three primary colors were also heavily used in De Stijl abstract art which influenced the Bauhaus movement. This painting by Piet Mondrian (Composition with Red, Yellow, Bluea and Black, 1921) demonstrates this (picture source: Wikimedia).
The biggest German tabloid newspaper Bild traditionally had a title page in red, black and white. This highly effective color combination is an absolute classic in graphic design and was already used in egyptian papyrii (headings and quantities written in red) and medieval manuscripts (rubrication). In the last years the newspaper has begun also using yellow-black titles as can be seen in the picture below (Source: Bild ePaper).