In a recent research paper titled “A New Way to Understand the Color Rendition Performance of Multi-Primary Light Sources” published in Leukos, the researchers introduce a novel approach to evaluating and characterizing the color rendition performance of tunable, multi-primary light sources—a class of modern illumination technologies with significant applications in architecture, entertainment, and display systems.
Traditional lighting quality evaluation methods, such as the Color Rendering Index (CRI), have limitations when applied to the increasingly complex and adjustable multi-primary (often LED-based) light sources. These light sources can dynamically vary their spectral power distributions, leading to a wide range of possible color rendition outcomes. Existing metrics like CRI or TM-30-18 provide fixed, often narrow evaluations and may not fully capture the full scope of variability enabled by multi-primary source systems.
The main goal of this study is to develop a new measure that can quantify the entire range of possible color rendition variation within a tunable, multi-primary lighting system—going beyond static, single-point metrics and considering the system’s potential spectrum of performance.
The researchers propose a measurement protocol that assesses how much a multi-primary lighting system can modulate its color rendition properties by adjusting its primary sources. They introduce a systematic method to map the boundaries of achievable color rendition metrics (such as fidelity and gamut) for any given configuration or combination within the system. This involves mathematical modeling to explore all allowable combinations of the primaries’ outputs within their operational limits and calculation of the resulting color rendition indices for each possible spectral mix. Visualizations, such as 2D plots, are used to portray the space of possible outcomes, highlighting the extremes and variability available to system designers and users.
The study demonstrates that multi-primary, tunable systems can exhibit dramatically broader and more varied color rendition properties than traditional (fixed-spectrum) sources. The new measurement approach illustrated how different settings within the same device can deliver high color fidelity, enhanced color saturation, or specialized rendering effects—often with trade-offs between these outcomes. Selecting a “best” spectral mix therefore depends not only on technical performance but also on application needs (e.g., retail, healthcare, art).
This comprehensive evaluative framework provides manufacturers, designers, and researchers with a tool to understand and optimize LED lighting systems for specific goals, be it natural color rendering or deliberate color enhancement. It also enables transparent communication to end-users about what a lighting product can and cannot do, and facilitates product comparison based on potential performance ranges—not just isolated test settings. Ultimately, the measure supports the development of smarter, more adaptive lighting that can be tailored in real time to suit diverse environments and user preferences.
By introducing a way to characterize and visualize the full spectrum of color rendition performance from multi-primary, tunable light sources, the paper addresses a critical gap in lighting assessment. The study’s protocol provides a pathway toward more flexible, application-specific, and user-centered lighting solutions by making the scope and limits of color rendition variability both quantifiable and actionable.
More information is available here.
Top image: The spectral power distributions of the set of 32 LED primaries used to create 132 color-mixed LED systems. https://doi.org/10.1080/15502724.2025.2507630
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