Understanding Standard Deviation Colour Matching

What is it, how it works and the importance of colour consistensy

Lighting has an inordinate influence over the environment, across all applications that it’s installed into. Therefore, it is important for the products to be suitable. The construction and manufacture of LED chips leads to natural variations, however slight, in emitted colour. This variable nature of colour means that a system, or method of understanding, is vital to be able to quantify how luminaries will perform.

Despite luminaires being listed as a certain colour temperature, like 3000K, there are differences in the actual colour temperature emitted, post installation. This is where SDCM becomes particularly useful.

SDCM is known as an acronym for Standard Deviation Colour Matching and synonymous with MacAdam’s or MacAdam Ellipses. The human eye is extremely strong at perceiving differences in colour, so the core function is to provide a method, a common metric, for every person to begin to understand the underlying colour quality of the luminaire that they’re looking at.

SDCM is on a scale from 1 to 10, with 1 being the value that provides the minimal amount of difference. A variety of SDCM values are acceptable for different applications. Typically, for interior and residential areas; 3 SDCM and lower is desirable.

Colour differences will not be noticeable to the human eye. When looking at commercial and industrial spaces; the SDCM requirements are generally wider, with 4, 5 and 6 acceptable.

This is, in part, due to the application putting a greater weighting on wider, long lasting functional lighting and greater spacing between products. High bays in a warehouse will have greater physical distance between them, compared to downlights in a kitchen, so differences will be less noticeable in reality.

The practicalities of SDCM LED binning means that it is more complex to manufacture chips with closer binning, therefore they are more expensive to make, adding to the price of the luminaire.

The technical datasheets, available for download on every product page, have a row dedicated to listing the SDCM. The product development process requires a stringent review of the LED chip choice, including SDCM, and we ensure that the most appropriate selection is made.

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