Human Centric Lighting Measurement
Human-Centric Lighting (HCL) is an approach to artificial lighting designed to harmonize with our natural biological rhythms and promote overall well-being. By adjusting the lighting brightness, color temperature, and intensity, HCL supports the body’s circadian cycle, helping to improve sleep, boost mood, and increase productivity. By replicating the qualities of natural daylight, it fosters focus and alertness during the day while promoting relaxation in the evening. Standardized by the International Commission on Illumination (CIE), HCL is particularly beneficial in workplaces, schools, homes, and healthcare environments, creating adaptive environments that prioritize comfort, health, and efficiency while seamlessly supporting the body’s natural rhythm.
The circadian rhythm, or the body’s internal clock, is a 24-hour cycle that regulates essential functions like sleep, body temperature, hormone production, and more. Synchronized with light and darkness, it drives daytime alertness and nighttime rest. Key phases include melatonin release at night, the body’s lowest temperature around 4:30 AM, and peak alertness at 10:00 AM. Furthermore, it also influences muscle strength, reaction time, blood pressure, etc., making it essential for optimizing performance and maintaining overall health.
The Link Between Human-Centric Lighting and Well-being
Lighting significantly impacts our well-being, shaping mental and physical health, productivity, and overall quality of life. Poor lighting can disrupt circadian rhythms, leading to fatigue and reduced productivity. Research consistently shows that improper lighting impacts our natural biological cycles, with far-reaching effects on our minds and bodies.
HCL addresses these challenges using tailored lighting strategies to align with our natural needs. By mimicking natural daylight, HCL supports the regulation of circadian rhythms and helps synchronize the body’s internal clock. Bright lighting during the day boosts mood, focus, and cognitive performance, while dimmed, softer lighting in the evening encourages melatonin production, paving the way for deep and restful sleep.
Furthermore, customized lighting for different activities can create more comfortable environments, reducing stress and visual discomfort.
Understanding How We Perceive Light
Photopic vision refers to the human eye’s ability to perceive light in well-lit conditions, such as daylight or bright indoor lighting. It enables color perception through cone cells in the retina and is responsible for daytime visual acuity. In contrast, melanopic vision relates to the body’s non-visual responses to light, particularly in regulating circadian rhythms. It involves melanopsin in retinal ganglion cells, influencing melatonin production and other biological processes independent of traditional visual perception. While photopic vision allows us to see clearly, the melanopic vision helps maintain our biological clock and supports overall well-being.
Illustrative example of 3000K LED with the melanopic (blue) and photopic (green) curves
The CIE S 026 Standard: A Foundation for Human-Centric Lighting Measurement
The CIE S 026 standard establishes a robust framework for accurately measuring and implementing HCL. It offers scientifically validated metrics and guidelines to help lighting designers or manufacturers assess the biological impact of light and optimize its use to enhance health, well-being, and productivity. By combining physiological insights with measurable parameters, the standard enables the creation of adaptable, human-centered lighting solutions tailored to our biological and visual needs.
At the heart of the CIE S 026 standard lies the focus on melanopic measurement parameters. These specialized metrics evaluate how light influences biological processes, ensuring it aligns with human comfort and activity levels while supporting natural rhythms.
Measuring Key Human-Centric Lighting parameters (Melanopic lux)
HCL emphasizes balancing melanopic and photopic lux to support circadian rhythms and visual needs. Photopic lux measures light as perceived by cone cells for visual tasks. Meanwhile, melanopic lux influences non-visual responses like circadian regulation and melatonin suppression.
HCL introduces dynamic Correlated Color Temperature (CCT) to replicate natural light patterns throughout the day. In the morning, cool and blue-enriched light, around 5000K to 6500K, increases melanopic stimulation, boosting alertness and productivity. By evening, warmer light, around 2700K to 3000K, can help reduce melanopic influence, encouraging relaxation and restful sleep. This dynamic shift optimizes biological processes, supporting health, mood, and overall well-being.
Illustration of color temperature
Konica Minolta Light Measurement Solutions for Human-Centric Lighting Measurement
Konica Minolta Sensing, a leading light measurement solution provider, offers a diverse selection of light meters tailored for lighting and luminaire design and manufacturing needs. Among its standout tools is the Konica Minolta Illuminance Spectrophotometer CL-500A, an indispensable tool for measuring key HCL parameters.
Lightweight and compact, the CL-500A is ideal for evaluating advanced lighting technologies such as LED and EL illumination. It delivers precise and reliable measurements across various lighting evaluation parameters, including illuminance, color temperature, color rendering index (CRI), chromaticity, and spectral power distribution. Furthermore, it can measure the scotopic and photopic illuminances, including calculating the S/P ratio.
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Illuminance Spectrophotometer CL-500A Video
Paired with the M-EDI software, the CL-500A offers precise and reliable measurements of melanopic equivalent daylight illuminance (M-EDI), a critical parameter for HCL as per the CIE S 026 standard. Along with the M-EDI value, it also provides the Ev, CxCy, and spectral graph for irradiance, S-con-opic, M-con-opic, L-con-opic, rhodopic, and melanopic.
M-EDI Software
Interested in learning more about the CL-500A and M-EDI software? Or perhaps you require assistance in finding a suitable light meter or measurement solution to support your lighting manufacturing or design? Contact us now for a free consultation and expert guidance.