LED SDCM – What is it, and how do I use it?
Have you ever installed a new batch of LED downlights on a new shop fit-out but found some aren’t quite producing the same colour of light as the ones beside them? Odds are that you’ve likely installed a batch of lights with a poor Standard Deviation of Colour Matching (SDCM) rating.
SDCM, typically applied when acquiring LED lights for an upcoming project, is used to guide light designers and lighting engineers in understanding how many colours of light can vary between fixtures. Minimal variance creates a professional and comfortable lighting experience; too wide a variance can result in a disjointed and uncomfortable experience.
To reflect this, a 1 SDCM rating reflects an essentially perfect match between lights, whereas a 7 SDCM rating creates a very inconsistent lighting colour arrangement for the environment.
The SDCM rating system is derived from work by well-known colour scientist Dr David MacAdam. In a 1942 experiment, MacAdam and his team tested 25 various target colours from the CIE 1931 colour space and began asking test subjects to compare colours on a screen. The results from this experiment determined that the area of acceptable colour variance isn’t a circle, but rather an ellipse, and depending on the target colour point, the area of acceptable colour variance may change in size and orientation.
From this study, they derived the MacAdam Ellipses. They applied them to the CIE1931 colour space, allowing light designers and engineers to determine the varying degrees of acceptance across those 25 target colours. The MacAdam Ellipses show the various steps or standard deviations from the target colour, with the distance between each determining the SDCM rating.
The SDCM system applies when purchasing batches of LED lights for an upcoming project, as using this principle for replacement purposes of individual lights will likely result in a disappointing experience.
If you have any questions about applying the SDCM principle to your next upcoming lighting project, the team at LED Supplies Australia are here to help! Send through any questions to the LED Supplies Australia team here.
