Most lighting manufacturers may pay close attention to the machinery and decor of their workshops, but they often overlook a critical factor: the lighting environment. In fact, lighting not only affects how clearly we see things but also profoundly influences our mood, alertness, and overall well-being.
Lighting: Beyond Just "Seeing"
Conventional understanding suggests that lighting is merely for clear vision. However, scientists have discovered a novel type of photoreceptor in the mammalian retina. These cells are not involved in image formation but are specifically responsible for regulating non-visual functions such as our circadian rhythm, alertness, and emotional state. This means that even when you don't rely on light to see objects clearly, illumination is still subtly influencing your physical condition. A field study conducted in three factories in Egypt revealed the profound impact of lighting characteristics on workers.
Researchers measured lighting parameters within the factories during different periods in both winter and summer, while simultaneously recording workers' self-assessments of comfort, mood, alertness, and satisfaction.
The results were surprising: changes in lighting levels showed a high correlation with changes in workers' psychological states.
Impact of Illuminance Level: The study found that when horizontal illuminance fell below 300 lx, workers' sense of relaxation, alertness, and emotional state significantly declined. In lighting environments between 300~500 lx, workers' non-visual functions showed marked improvement.
Impact of Time Factor: Workers' alertness and mood exhibited clear fluctuations throughout the day. After 4:00 PM, all metrics began to decline, with this negative effect being more pronounced, especially during night shifts.
Specific Impacts of Lighting Parameters
Vertical Illuminance is More Important than Horizontal Illuminance: The research indicated that light on vertical surfaces (light falling on the human face) had a greater impact on the sense of relaxation than horizontal illuminance on work surfaces.
Limited Impact of Color Temperature (CCT): Contrary to expectations, Correlated Color Temperature (CCT) had a relatively minor effect on most non-visual functions, showing results only under specific conditions.
Benefits of Dynamic Lighting: Studies showed that lighting systems simulating natural light variations were more beneficial for workers' well-being compared to static artificial lighting.
BLED Lighting’s advice for Designers as Follows:
Ensure Sufficient Illuminance
Work area illuminance should not fall below 300 lx, with an ideal range of 300~500 lx. Particularly for night shift environments, sufficient lighting must be provided to maintain workers' alertness.
Prioritize Vertical Lighting Design
It's essential to consider not only horizontal illuminance on work surfaces but also, more importantly, the vertical illuminance reaching the human eye. Reasonable vertical lighting can significantly enhance workers' sense of relaxation and comfort.
Simulate Dynamic Changes of Natural Light
Design lighting systems capable of simulating natural light variations, automatically adjusting lighting characteristics based on the time of day to help maintain workers' normal circadian rhythms.
Design Dedicated Lighting Schemes for Night Shifts
Nighttime lighting requires special consideration. It is recommended to adopt lighting systems that can simulate daylight effects to mitigate the negative health impacts of shift work on workers.
Consider All Lighting Parameters Comprehensively
Design must simultaneously consider multiple parameters such as illuminance, color temperature, and Color Rendering Index (CRI), as they collectively influence the non-visual effects of lighting.
Our New Understanding of Lighting Design through this study
Good lighting design is not merely a technical issue; it is human-centric design concerning people's health and well-being. While pursuing energy efficiency and environmental protection, we must pay greater attention to the deep-seated impact of the lighting environment on human health. The future of lighting design will inevitably be a journey transitioning from "lighting up spaces" to "lighting up lives."