Local context
It is also important to take the sign’s specific purpose and location into consideration. Will it be displaying text, animation, still graphics and/or video? Where will most of the display’s audience be and how fast will they be travelling? If there is a stoplight nearby, that may be the ideal ‘marker’ to use as the estimated viewing distance line.
The size and resolution of the display will also depend on the nature of its content. Many LED boards are still dedicated to simple, monochrome messaging.
Pylon space, permits and, of course, the customer’s budget will also affect the size of the chosen display. While many customers want the highest-resolution display possible, that is not necessarily what they need, given the circumstances of their location.
By way of example, one can consider the two displays listed in Table 1, which carry the same cost of approximately $70,000, but are different sizes. At 12.5 m2 (135 sf), the 20-mm pitch display is 170 per cent larger than the 10-mm pitch display at m2 (50 sf), even though the 10-mm display has 41 per cent more pixels: 39,168 versus 27,648.
So, if a customer had that budget of roughly $70,000, he/she could choose an LED display with a 10-mm pixel pitch and minimum character height of 71 mm (2.8 in.) or a larger model with a 20-mm pixel pitch and minimum character height of 140 mm (5.5 in.). Every additional 25 mm (1 in.) of letter size adds 15 m (50 ft) of legible viewing distance.
If highway drivers are passing the sign at an average of 97 km/h (60 mph), the display with the 20-mm pitch enjoys an advantage of 27.5 seconds more viewing time, due to its 80 per cent greater viewing distance. To achieve the same effectiveness, the 10-mm pitch display would have to be significantly larger, bringing its cost close to $200,000.
A matter of math
This is why it is always better and easier to show customers through simple math which display will be the most cost-effective for their needs, rather than rely on hype or factory representatives’ technical presentations. And in the end, selling the right display to the user is the best way to ensure he/she remains a loyal customer in the future. As always, the sign industry’s growth depends on integrity.
Robert Blyth is a senior technical advisor for Optec Displays in St. Hubert, Que. For more information, visit www.optec.com.
