Lighting the way: How we choose brightness & colour temperature in our solar lamps
Since 2014, BRIGHT has been at the forefront of solar lighting innovation, designing and supplying sustainable solar lamps that cater to off-grid communities, humanitarian aid missions, and disaster response scenarios. Our LED solar lights are meticulously engineered to provide optimal brightness and appropriate colour temperature, enhancing safety, supporting education, and preserving dignity in diverse settings. With over 4.3 million solar lamps delivered, we have illuminated the lives of more than 17 million people worldwide.
The science behind brightness and colour temperature
BRIGHT solar lamps use light-emitting diodes (LEDs) to provide reliable and efficient lighting. The brightness of an LED is measured in lumens (lm), which indicates the total visible light it emits. Higher lumen values mean brighter light. Meanwhile, the colour appearance of light is determined by its colour temperature, measured in Kelvin (K).
- 2000K to 3000K: warm, yellow-red light (like candlelight or incandescent bulbs)
- 3500K to 4500K: neutral white light, balancing warm and cool tones
- 5000K to 6500K: cool, bluish-white light resembling daylight
Balancing performance with user comfort
BRIGHT solar lamps typically operate within brightness ranges of 1.5 to 300 lumens, and colour temperatures between 4000 K and 6000 K. These choices are not arbitrary, they stem from rigorous field testing and user feedback.
Line Iren Andersen, Head of Research and Development and Manufacturing at BRIGHT, explains that design decisions are shaped by customer requirements, regional preferences, and broader market trends.
For instance, a 4000 K colour temperature was a requirement by UNHCR, while 5500 to 6000 K is commonly preferred by consumer markets. To enhance user comfort and minimize eye strain from overly blue light, we are working to standardize the colour temperature of our full product line to 4000 K.
Line notes how regional preferences influence choices too: "Scandinavian countries like Norway often favour warmer tones due to dark winters, while areas in the Middle East, Asia, and parts of Africa tend to prefer cooler, bluer light."
BRIGHT’s shift towards 4000K colour temperature across its product line also aims to differentiate the company from industry norms, where manufacturers often opt for high-Kelvin LEDs. We believe comfort and context should outweigh generic trends.
Why lower lumens make sense in the field
The industry trend of marketing lamps with high lumen output has created pressure to increase brightness. However, BRIGHT’s focus is on designing lamps that truly meet user needs. This means prioritising battery efficiency, runtime, and practical features like an emergency blinking light over maximum brightness.
In Uganda’s Bidibidi refugee camp, field tests of our SunBell and Sol models revealed that users preferred the lowest or second-lowest brightness settings. Their goal was to conserve battery life across cloudy days and maintain a calming environment for sleeping or caring for babies. Lower brightness also allowed visibility of potential hazards like scorpions without overwhelming glare.
Technical limitations also come into play. Placing too many LEDs close together can reduce light quality and increase flickering risks. Instead of chasing lumen highs, we aim to develop adaptable, efficient lighting solutions.
Practical innovations driven by user feedback
Some of our best product features have originated from the field. A key partner once required a six-hour runtime at maximum brightness and an emergency blinking light feature. These requirements are now standard across our range of products.
Line says BRIGHT is also exploring new features such as red light functionality, ideal for night vision, especially in places where there are mosquitoes; and expanded use of reflectors to enhance perceived brightness without draining more power. Currently, reflectors are used in the SunTurtle, SunBell, and Move solar lamp.
Designing for real use cases
"It’s crucial to differentiate the use case of each lamp," Line explains. "A headlamp or task light serves a different purpose than a lantern that lights up a room or tent."
Line shares how her 5-year-old son prefers the directional beam of the SunBell for drawing, the ambient glow of the Sol as a night lamp, and dislikes the Move lamp due to its intense brightness, even at its lowest setting (20 lm).
She explains that a wide but controlled lumen range would be ideal as ultra-low brightness is often more important than high-intensity modes, based on real-world use
“I envision a product line where every lamp has an intuitive interface, a wide but practical lumen range from as low as 2-3 lumens to 300 lumens, and lightweight, durable construction tailored for its primary use,” says Line.
Lighting designed around lives
By grounding our engineering decisions in real-world insights and human needs, we ensure BRIGHT solar lamps bring comfort, safety, and dignity to the communities we serve. As we continue to innovate, BRIGHT remains committed to thoughtful, user-first design choices that put people’s well-being before industry trends.
Explore our sustainable solar lamp solutions, learn more about our design process, or get in touch to discuss partnerships that make a difference.