CKRA LED Color Uniformity and Consistency

Most of human sensory information is visual, coming to us through reflected light. Color consistency describes the non-variation in color from light source to light source, and fixture to fixture. We often don’t realize that we are influenced by the uniformity of color, but we always respond to it.

Let’s say you drive by two gas stations. Station A is illuminated throughout by bright white LEDs, while Station B’s lights vary from yellow to white and one panel is dim. You will likely go to Station A because its color consistency feels comforting and high quality, even if you aren’t conscious of that decision.

The difference in color between two lights is defined by an industry-specific standard called the MacAdam Ellipse. Each time the human eye can detects a color shift, it is measured as a MacAdam Ellipse step. In a range of 7 steps, the smaller the step, the more consistent lights are in color.

Color matching looks for the color consistency between light sources. Light appears white as it runs along a blackbody curve through the center of the color spectrum. When phosphor-based sources like LEDs vary from the blackbody, that variation is referred to as a tint. Light sitting above the blackbody curve has a green or yellow tint, and light below has a blue or pink tint.  Color points that are plotted close together on the blackbody curve appear to match.

Seasoned manufacturers create products with a tighter distribution of color points and less variation in tint. This results in smaller MacAdam Ellipses, satisfied lighting specifiers and, most importantly, a great user experience.

Light sources with color points that do not match are less effective. Back at Station B, the outside canopy is lit with white LEDs, all 4000K, from the same brand and manufacturer. But one panel has a green tint, the next panel is yellowish, and the third is a little pink. These unmatched tints trigger the emotional discomfort that drives you to the beautifully matched white lights of Station A.

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