Chromatic coordinates

The understanding and application of chromatic coordinates are fundamental in the field of lighting, especially for designers and manufacturers seeking precision in the color representation of light sources.

In this article we will explore the importance of chromatic coordinates, detailing their definition, application and relevance in the quality control of LED (light emitting diode) lighting.

Definition of chromatic coordinates

Chromatic coordinates are a numerical representation that allows us to accurately identify the colorimetric characteristics of a light source.

They are defined within a coordinate system, commonly the CIE 1931 XYZ chromaticity diagram, where ‘X’ and ‘Y’ represent the position of a specific color within this space.

This system is based on color theory and is essential for understanding color perception in lighting applications.

Location and meaning of the coordinates

In the chromaticity diagram, the coordinates are demarcated on a graph whose ends are defined by the basic RGB colors (red, green and blue). This graph makes it possible to visualize how these primary colors are mixed to produce the full spectrum of colors perceived by the human eye.

Central to the diagram are the white tones, which range from 1,000ºK (a white with a yellowish hue) to 20,000ºK (a white with a bluish hue). This range represents color temperature and is critical for designing lighting applications that seek to simulate natural daylight conditions or create environments with specific color temperatures.

MacAdam ellipses and color perception

A key aspect in the study of chromatic coordinates is the concept of MacAdam ellipses. These ellipses represent regions within the chromaticity diagram where color changes are undetectable or barely perceptible to the human eye.

The distance between these ellipses is measured in SDCM (Standard Deviation of Color Matching).

SDCM in lighting is a metric that quantifies the perception of color differences between light sources.

A low SDCM indicates minimal, almost undetectable color differences, ensuring high consistency and uniformity in the perception of color quality in lighting.

Higher values indicate easily perceptible color differences, relevant in applications where color accuracy is critical.

Essentially, SDCM is vital for maintaining LED quality control standards and color consistency in lighting design.

1 SDCM**: Undetectable color differences.
2-4 SDCM**: Barely visible differences.
5 or more SDCM**: Clearly noticeable differences.

This metric is vital to ensure consistency in the production of light sources, where color variations are minimized so as not to affect visual perception in critical applications, such as the lighting of workspaces, museums, and retail establishments.

Practical application of chromatic coordinates

In practice, the use of chromatic coordinates allows lighting designers and manufacturers to specify and reproduce colors with high precision. This is especially important in projects where color fidelity and consistency between different lighting units are critical.

For example, in lighting design for commercial spaces, a slight variation in LED color temperature can affect the perception of the product and thus the consumer experience.

Similarly, in the artistic or museum environment, the correct chromatic reproduction is fundamental for the proper appreciation of the artwork.

At Actilum, we are dedicated to excellence and innovation in LED lighting applied to professional lighting solutions and design, committing ourselves to the development of products that not only meet the highest standards of quality and energy efficiency, but also adapt to the specific needs of our customers.

Our focus on advanced lighting technology, LED color accuracy and consistency, backed by the rigorous application of metrics such as SDCM, ensures that every high-quality lighting solution we design enhances the visual experience, ensuring color fidelity and uniformity across all lit spaces.

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