{"id":3279,"date":"2022-10-31T02:30:01","date_gmt":"2022-10-31T02:30:01","guid":{"rendered":"https:\/\/ledask.com\/?p=3279"},"modified":"2022-10-31T09:45:43","modified_gmt":"2022-10-31T09:45:43","slug":"macadam-ellipse","status":"publish","type":"post","link":"https:\/\/ledask.com\/macadam-ellipse\/","title":{"rendered":"MacAdam Ellipse: Color-Consistent Regions for Standardizing Light Source Colors"},"content":{"rendered":"\n
Color consistency plays a huge role in the perceived light quality in interior spaces. So when buying luminaires, keep in mind their light color output is critical, especially if you want to install multiple light sources in one continuous area. The MacAdam ellipse plays a significant role in helping us understand the color differences in LEDs because it helps standardize light colors. We will analyze it in detail to show you how it helps create color-consistent LEDs. Let’s get right into it!<\/p>\n\n\n
A MacAdam ellipse<\/a> is an area on the chromaticity diagram<\/a> that contains all indistinguishable colors. The CIE chromaticity diagram has been applicable since 1931, hence its name, the CIE 1931 color spaces.<\/p>\n\n\n\n The CIE 1931 XY chromaticity diagram<\/em><\/p>\n\n\n\n The name MacAdam comes from David MacAdam, a scientist who experimented with color perceptions and chromaticity differences. He then transferred the results to the flat chromaticity diagram and measured 25 ellipses, with the contour of one representing the JND (just noticeable differences) in color matching.<\/p>\n\n\n\n The experiment proved that an average human eye could not spot the color differences in the ellipse regions from the MacAdam ellipse’s center.<\/p>\n\n\n\n Standard Deviation Color Matching (SDCM) has roughly the same meaning as a MacAdam ellipse. LED lighting uses color deviations in MacAdam\/SDCM ellipses to define a light source’s color precision.<\/p>\n\n\n A 1-step MacAdam ellipse is a zone in the CIE 1931 XY chromaticity space where a human eye cannot detect color variations. Therefore, it is the elliptical area where observers identified and determined that it has the same color.<\/p>\n\n\n\n The experiment showed that humans have a more challenging time spotting chromaticity differences in green color. So you will notice ellipses in the green section are broader than those in the blue region. Therefore, these green zones have more expansive MacAdam steps than blue color zones.<\/p>\n\n\n The human vision system has highly tuned senses for color perception. If the chromaticity coordinates of two LED lights fall within a 1-step SDCM ellipse, you will not observe any color difference. If the variation falls in an area twice as large (2-step MacAdam ellipse), you will spot slight color differences. A 3-step zone will show more chroma differences.<\/p>\n\n\n\n If we consider the size of a 1-ellipse step to be 3,000K color temperature, then the CCT range will be +\/-30K. So it will take a tiny change of +\/-30K to detect the light sources are color inconsistent.<\/p>\n\n\n\n The white color temperature scale<\/em><\/p>\n\n\n\n Here’s how the differences fare.<\/p>\n\n\n\n But the importance of color consistency depends on the application. For instance, detecting deviations in outdoor lighting is more challenging because the visual receptor experiences the Purkinje effect<\/a>.<\/p>\n\n\n\n The effect defines the tendency of the eye’s sensitivity to peak illuminance shifting towards the blue light spectrum in low light levels. The diminished color detection plus wide spacings in outdoor lighting make color consistency a non-critical factor in street lighting, parking lots, and other exterior lights.<\/p>\n\n\n\nWhat is a MacAdam Step?<\/h2>\n\n\n
What is the Importance of Color Consistency in LED Light Sources?<\/h2>\n\n\n
SDCM\/MacAdam Ellipse<\/strong><\/td> Visibility<\/strong><\/td><\/tr> 1 SDCM step<\/td> Almost zero visible deviations<\/td><\/tr> 2 SDCM steps<\/td> Deviations noticeable using instruments<\/td><\/tr> 3 SDCM steps<\/td> Few differences noticeable by the human eye<\/td><\/tr> 4 SCDM steps<\/td> Visible deviations<\/td><\/tr> 5 SDCM steps<\/td> Clear and visible deviations<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n Color Consistency Outdoors<\/h3>\n\n\n