The design principle of proximity organizes layouts so that they can be read easier and quicker. What is proximity? It is the moving of design elements closer together or further apart. The goal is to create groupings.
Grouping design elements by proximity makes the message easier to comprehend, because it helps the viewer connect related elements without effort. It makes thought groups clear, where one piece of information ends and another begins.
A mistake that many novice designers make is to fill up a sign with the largest possible lettering and graphics. The result is that there is no clear separation between crowded thought groups and the composition becomes a chore to decipher.
Part of the problem is that an inexperienced designer fears white space, believing that by reducing it the letters can be made larger and “easier to read.” This is self-defeating because the resulting layout has a busy, crowded look that appears disorganized and is actually more difficult to read. Such a layout can look like too much work to a viewer. It is easily ignored. —for a comprehensive discussion of the importance of not making a viewer work to comprehend a message, see Don’t Make Me Think Revisited by Steve Krug (2014). While his discussion centers on web page usability, it applies with equal force to sign layout.
The importance of proximity, creating groupings, is especially important when copy is heavy.
When a client insists on a sign with heavy copy it puts a great burden on readability. Heavy copy, in itself, is a strike against a layout. It should be taken for granted that a significant number of viewers will ignore the sign because of heavy copy alone. But we can still make it readable, inviting, by using proximity, aggressively corralling copy into copy blocks surrounded by generous margins. We can create the visual impression that the layout is less busy than it really is.
A menu sign is an excellent example of a sign that usually has heavy copy, but that can be tamed by using margins and clear separations of menu items. Clarity on a menu is absolutely critical. The proximity principle can make it happen.