Stand back... way back, way-way back and look at your design on the monitor. What can you see? Can your eyes pick out the letters and recognize them? Can you read the message on the sign? Will it stand out in a sea of visual clutter in the real world?

 

Designing monument signs is a balancing act of blending parameters, colors, objectives and graphics into a monolithic mass of aluminum and electricity whose only function is to be noticed, to inform and to bring in revenues for the one who paid for it.

 

In discussing the effectiveness of a sign, we must address three factors that dominate the design process: visibility, legibility and readability. They are defined as follows:

 

Visibility: The purpose of having a sign is so the intended audience “notices” the sign and reads the message. Why do you think truck stops along the interstate use 100' tall pylon signs with 8' tall gas price numbers? Visibility is about being seen: Can you see the sign from the highway, yes or no? There are at least four factors that affect visibility: shape, size, color and location. An effective sign is one that makes the best use of all four of these factors based on the environmental conditions at hand. 

 

Legibility: In the sign industry, this means, “Can you tell if that is a capital D or a lowercase P from 300 feet away?” Does the font have a unique style that makes it hard to recognize? If so, you may want to reconsider your options. (See Example A)

 

Some fonts are just not made for outdoor use; they are not legible at a distance and can make a sign layout difficult to read.

Readability: Have you ever looked at a sign with a lot of copy and felt your eyes strain while reading it? If your eyes strain, the designer either used the wrong font, the wrong size of letters or incorrect spacing and kerning, conflicting colors... the list goes on and on.

 

The definitions and differences between readability and legibility have been part of the literary world since the dawn of the pencil. Occasionally I am corrected on my usage of the words Legibility and Readability, and to reinforce my case, here is what Wikipedia has to say on the subject: 

 

“One of the clearest distinctions between the two concepts (legibility and readability) was presented by Walter Tracy in his Letters of Credit. These… ‘two aspects of a type’… are… ‘fundamental to its effectiveness. Because the common meaning of “legible” is “readable” there are those—even some professionally involved in typography—who think that the term “legibility” is all that is needed in any discussion on the effectiveness of types. But legibility and readability are separate, though connected aspects of type. Properly understood… the two terms can help to describe the character and function of type more precisely than legibility alone.”

 

Thanks Wiki. While Wikipedia may not be the most reliable source for information, in this instance I couldn’t have said it better myself.

 

Let’s get started 

Visibility as it relates to structural design, size, colors and location of the sign:

Look at the space where the sign is to be installed. Is there plenty of visibility from all directions? Are there trees or buildings that could block the view? How tall should it be and what are the color options available? These are the questions to ask of your salesperson as they head out the door for the survey. Your survey should include a 360 degree view of the area to see if there is anything that would detract from the sign. (Overhead power lines, large trees, overpasses and highway signs, etc.)

 

Optimum legibility: Letter style, size, color, spacing

If your sign is 35' tall and you need it to be legible and readable at 300 feet, what formula do you use to calculate letter height? Calculating this is fairly complex and involves the use of a left handed abacus, however an easy shortcut is to simply add a zero to the letter height (in inches) and convert the number to feet.

 

Example: Start with your letter height of 6", then add a zero to it and change the measurement from inches to feet. That means a 6" tall letter would have an optimum legible distance of 60'. Letter 4"tall are best read at 40' and 12" tall letters are best viewed at 120', and so on.

 

To have optimum legibility at 300 feet, the letter height needs to be at least 30" tall. Many of the digital display and plastic letter companies offer useful charts that show letter height readability distances for letters from 1" all the way to 60" tall. Posting one of these charts near your desk is always a good measure.

 

Let’s start with some examples of sign layouts where color, contrast and font style have drastic effects on the sign’s effectiveness. In the following examples, the same sign is shown at three different distances. We’ll say that the left sign is 50' away, the middle is 100' away and the sign on the right is 150' away.

Notice in the first example (See B) that the primary tenant logo is legible and readable even at the 150' distance. Now change one element, such as the background color and notice how difficult it is to read at all three distances. (See C) Replace the dark background and now change the font. Notice the legibility drops drastically on the middle example and it’s impossible to read at the 150' example. (See D) The curly cues and stylized letter stroke add visual clutter that interferes with our brain’s ability to recognize the letter.

 

Excellent contrast of cream colored text on a dark background. Proper balance of negative space provides legibility and readability.

Contrast of colors is just as important as a font’s legibility. This lighter colored background forces the eye to work harder.

Although even a novice designer would never use this font in all caps, it illustrates how some fonts are best left for invitations and diplomas, not signs.

You can see in the example where I substituted a massive, heavy font (see E) how it has increased the legibility at all distances; however, this font does not fit the image of the restaurant and would not be the best choice. In each of the following examples, you can see how font style, size, spacing, color and layout affect the sign’s readability, which directly relates to the effectiveness of the sign. 

 

Adding a heavy bold font increases legibility and readability, however a bold font does not accurately represent restaurant’s “South of France” ambiance.

In conclusion, as with any sign design, it must be readable (not to be confused with legible). The factors affecting readability relate to the height of the letters, the font style, the colors or contrast surrounding the letters and the layout or spacing of those letters. Knowing the optimum distance for viewing the sign is the first step to calculating letter height, then understanding the definitions of legibility and readability is the second step. Throw in color contrast management and you’re on your way to a great design.