Sign & Digital Graphics

September '18

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28 • September 2018 • S I G N & D I G I T A L G R A P H I C S ELECTRIC SIGNAGE at lower CCTs (4000-5000K) and cooler colors (blue, green, etc.) render better with higher CCTs (6000-7500K). Temperatures below 3500K and above 7500K are typically not recommended, as they can cause significant color copy shift. For example, a 9000K LED can give red copy a purple hue and a 3500K LED can make blue copy look green- ish. If there are colors other than white on the sign, it is a good practice to use LEDs between 6000-7000K, which is the part of the color spectrum with the least amount of hue variation. Choosing the Right White White channel letters are completely a matter of preference. Often, I see many sign companies and end users leaning toward the 6500-7500K C C T range. The reason is usually perceived bright- ness and getting a "white" white. If you take a 4000K LED and a 7000K LED at the exact same lumen brightness and backlight a piece of white acrylic and ask someone which is "brighter," almost everyone will point to the higher CCT LED. This has to do with the human eye and the sensitivity differences of the rods and cones in our eyes. Most people view signs at night and peak scotopic vision is around 510 nm (in the blue-green region). So even though the total lumens Figure 3: Street Fighter Standard White LED modules at 3500K, 5000K, 7000K, and 9000K behind a white acrylic face. Figure 4: The Bon-Ton, located at the Lycoming Mall in Muncy, Pennsylvania, was retrofitted from neon to LEDs with Principal LED's Street Fighter Heavyweight in 7000K. In the long run, LEDs can decrease costs because of the low amount of maintenance associated with them.

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