Part 4: CLEVR Readability for Dynamic Digital Signs
Part 4: CLEVR Readability for Dynamic Digital Signs
If you are following this series, you know we are talking about the science behind good sign design, and how this applies to digital sign content as well. In our first post, we reviewed content considerations as a whole. This brought us to Part 1, CLEVR acronym for Conspicuity, Legibility, Visibility and Readability. We reviewed Conspicuity and what it means in the application called Dynamic Signage. Part 2 discussed Legibility, and how this relates to dynamic content for digital sign systems. Visibility and a great tip for improved dynamic signage was presented in Part 3. If you haven’t read up on the premise, do so with the links above.
And now, to complete the series, Readability is our subject today!
A readable display allows people to quickly and accurately recognize and understand information, in particular, alphanumeric characters. The message should be clear and unambiguous. In traditional sign design, a few words to convey important information is all that is required. The same can be applied to dynamic signage. Again, these displays are not television. It is not a seated audience, for the most part, watching the screen with no other distractions. In an ideal world, there would be nothing but the screen. In reality, there is likely to be other signage, noise, people milling around, and multiple distractions. The dynamic display message, therefore, should be built much like static signage.
This means the concept of readability takes on great importance. If you have only a few minutes to engage your viewer, you should make certain your message is readable – that the message is conveyed quickly and clearly. While we love our HD content, LobbyPOP always includes on-screen text and clear voice-over in bite-sized chunks to assure no part of the message is obscured or lost. Text is often white with a pin-line outline, to assure it shows clearly on any motion background.
Dynamic Signage displays are alphanumeric displays, using letters and numbers, along with graphic images and sound, to convey messages. The contrast ratio for the characters is an important element in readabiliy and legibility.
In their book, Human Factors in Simple and Complex Systems, Robert W. Proctor, Trisha Van Zandt explain that under optimal conditions, for black text on a white background, the font stock width-to-height ratio is ideally 1:6 to 1:8. For white characters on a black field, the optimal ratio is 1:8 to 1:10. Thinner lines for white on black images are required because of a phenomenon called radiation or sparkle. This is where the light color “bleeds” together due to the contrast -the eye’s reaction.
Keeping the core message concise, and the entire message in a ten to fifteen second clip, is a good rule of thumb. This does not mean that a 30-second spot is not desirable. On the contrary, the core message can be emphasized and repeated in ways that assure readability and recognition. This is the heart of all advertising: Repetition. So whereas traditional static signs can be read several times over in the space of a few seconds, thereby assuring a point is communicated, a dynamic sign can enhance this and “force” repetition upon the viewer by repeating the same points in slightly different ways, with supporting information in concert, much like bullet points in a presentation.
How many words? How much information per minute? We have validated that seven words or less for the core messaging, and up to eight supporting messages within a 60-second spot can be read and comprehended. So go forth and multiply your advertising!
Next post: The Power of Imagery – why this is in the wheelhouse of dynamic digital signage!
