I found this interesting article posted by Design Work Plan and found it so useful I had to share it. We’re reposting it because one problem we run into when trying to work with an already established design is how it contrasts with the actual sign color. You can find the original article here, or read more below:
This article is an introduction to signage color and contrast. You will learn about the contrast ratio for displaying text on a (colored) background for signs.
The article will explore the meaning of color and how to differentiate color in information layers.
Contrast between the foreground and background is one of the most important factors for the ease of reading. If coloured text is used on a bright background the contrast will be weak, for optimal contrast results is white text against dark colored backgrounds. In signage & wayfinding design color is the combining factor to harmonize the sign with the environment. Color programs will distinguish signs from each other and can offer an indication of the message without having to be able to understand the language of the sign.
Basics of color groups: Color wheel
Swiss painter and designer Johannes Itten created a color wheel that is a organization of 12 color hues around in a circle showing relationships between the colors. The colors are presented in the following way:
- Primary colors: Blue, red & yellow
- Secondary colors: Green, orange & violet
- Complementary colors: Red–orange, red–violet, yellow–orange, yellow–green, blue–violet & blue–green.
Goethe’s Theory of Colours provided the first systematic study of the physiological effects of color (1810). His observations on the effect of opposed colors led him to a symmetric arrangement of his color wheel, “for the colours diametrically opposed to each other… are those which reciprocally evoke each other in the eye.” (Goethe, Theory of Colours, 1810) (via wikipedia)
A Color Wheel is an abstract illustrative organization of color hues around a circle that shows relationships between primary colors, secondary colors and complementary colors. Knowing the relationship between colors is the first step in developing a color scheme for signage and wayfinding systems.
Color contrast by science
Arthur & Passini described in their book Wayfinding from 1992 a reliable calculating method to calculate the contrast difference between two colors. The formula is based on the light reflectancy (LR) readings in percentages for each of the two colors involved. By substracting the darker color from the lighter color, divided by the difference by the lighter, and multiplying by 100, we get brightness differential. When the brightness differential is 70 percent or higher the legibility is assured. When it is less, the legibility cannot be assured and those colors should not be using in that combination.
Color examples and meaning
Advisable work areas: Airport signage, office building signs, visual overwhelming environments, hotel signage, indoor usage.
White backgrounds can be used specific sign projects where design plays a bigger part than the actual wayfinding. For instance using silver lettering on a white background can give fabulous results, due the shadow of the silver lettering the text becomes readable on the white surface.
Advisable work areas: Museum signage, office building signs, pylon signage, retail signage, hospital signage, indoor & outdoor usage.
Red is a very powerful color which stands out in a visual crowded environment. I have seen various other signs produced with red but in my opinion red is a signal color. Works great with black, white and yellow lettering.
Advisable work areas: Warning signs, public spaces, indoor & outdoor usage.
Also for traffic signs yellow works good as background color in combination with black lettering. In a outdoor situation, yellow stands out from its background giving a clear message. In many European countries yellow is chosen as background color.
Advisable work areas: Airport signage, road signs, public spaces, indoor & outdoor usage.
To use blue in sign systems beware of create enough contrast in order to make the signs work best. For instance with light blue a higher contrast lettering will be needed such as black and for dark blue white lettering will work best.
Advisable work areas: Highway signs, railway signs, hotel signage, retail signage, public spaces, indoor & outdoor usage.
Advisable work areas: Office signage, nameplate design, public spaces, indoor & outdoor usage.
Typography & color contrast
Not only is the contrast important also the chosen typeface will make the difference in a good or bad sign. When using too bold weighted typefaces the text will look like its expanding of the sign, when using too light weighted typefaces the text will fall back into its background. Medium or Regular weights are usually the best options to choose for a good and readable sign.