Henrik Clausen: A Life Filled With Light

Where did your interest in light first begin, and what made you want to build a career around it?

My relationship with light developed gradually. I began working as an engineer in illuminating design at Louis Poulsen in 1987, supporting both product development and lighting planning. At first, light was something technical – something that could be calculated, measured and controlled.

Over time, I began to understand and appreciate what lighting can do for people. It shapes how we perceive a space, how comfortable we feel and, ultimately, how we experience everyday life. That understanding grew into a genuine passion. I sometimes say that I simply happened to live a life filled with light – but once I recognised its human value, I knew it was something I wanted to devote my career to.

What were some of your earliest roles in the industry, and how did they shape the way you think about light today?

In my first role as an illuminating design engineer at Louis Poulsen, I assisted research and development with optical design and supported the sales organisation with computer-based lighting planning. I later worked with quality management, international approvals, testing and technical documentation before becoming Head of Operations and Service.

I came to understand that good lighting is not created by one discipline alone. It requires design, engineering, research, manufacturing, quality and a thorough understanding of the people who will ultimately use the space.

My technical background taught me the importance of evidence and measurement. My later leadership and educational roles taught me something equally important: knowledge only becomes valuable when it can be understood, shared and applied.

What does your role at Fagerhult involve, and what are your main areas of focus?

I am Director of Fagerhult Lighting Academy and Head of Research at Fagerhult. I established the Academy to gather, refine and communicate knowledge about lighting to colleagues, customers, universities and the wider lighting community.

My research work focuses particularly on the relationship between lighting, people and health. I help connect scientific knowledge with product development and practical lighting solutions. Education is also a central part of my role. I lecture internationally and teach lighting design at Aalborg University, which creates a valuable bridge between academia, industry and professional practice.

Across all these activities, my purpose is the same: to use knowledge about light to add value to people’s lives.

How has our understanding of the relationship between light, people and wellbeing changed over the course of your career?

When I began my career, the industry’s attention was largely directed towards visual performance: whether there was enough light to perform a task, whether glare was controlled and whether the installation met the relevant standards.

Those things remain essential, but we now understand that light affects much more than vision. It influences our biological rhythms, alertness, comfort, mood and general sense of wellbeing. We have moved from thinking mainly about lighting spaces to thinking about lighting for people.

This has broadened the designer’s responsibility. A lighting solution should not merely satisfy a table of numerical requirements. It should respond to the activity, the architecture, the time of day and, most importantly, the needs of the people occupying the space.

Have any findings during your career fundamentally changed your own understanding of how light affects people?

The growing evidence for light's non-visual effects, which I touched on earlier, was a big turning point for me. Realising that the light entering the eye contributes not only to sight but also to the regulation of our internal body clock fundamentally changed how I thought about lighting.

It demonstrated that illuminance on a horizontal working plane tells us only part of the story. We must also consider the light that reaches the eye, its spectrum, its timing and its duration – as well as the darkness people need at other times.

The measurements matter, but they must always be interpreted in relation to human beings and their daily lives.

How do you translate scientific findings into guidance that designers, architects and specifiers can apply to real projects?

I believe everyone should share knowledge about lighting. To achieve that, those of us involved in research must be willing to step down from the pedestal and replace scientific language with plain, accessible language – without losing the integrity of the science.

I try to begin with the human question: What are people doing in this space, when are they doing it, and what do they need from the light? From there, research can be translated into practical principles, design choices and questions that project teams can use.

I don’t simply want to tell designers which number to achieve. I want to give them enough understanding to make informed decisions and to evaluate whether a lighting solution genuinely works for the people using it.

Is there a particular research project, lighting concept or piece of work that you are especially proud of?

I am especially proud of establishing and developing the Fagerhult Lighting Academy, which has created a platform for sharing research, practical experience, and knowledge globally.

The Academy has allowed me to work with an exceptionally broad community – lighting designers, architects, engineers, students, researchers and end users from many different cultures. That exchange is important because knowledge should not remain isolated within a laboratory or a company. Its true value emerges when it helps people ask better questions and create better environments.

I was deeply honoured to receive the Society of Light and Lighting’s President’s Medal in 2020 for a lifetime contribution to lighting. For me, its significance lay not only in personal recognition, but also in its recognition of education and knowledge-sharing as important contributions to our industry.

What do you believe we still do not fully understand about light?

We have learnt a great deal, but there is still much to understand about how different people respond to light over time. Human beings are not identical instruments. Age, health, individual sensitivity, previous exposure, behaviour and culture can all influence our needs and responses.

We also need to understand more about the combined effects of light’s intensity, spectrum, direction, timing and duration in real environments. Laboratory findings are essential, but everyday life is complex. People move between daylight and electric light, indoors and outdoors, activity and rest.

The challenge is therefore not simply to discover individual effects. It is to understand how we can apply that knowledge responsibly while still creating spaces that are comfortable, beautiful, sustainable and adaptable.

Has working so closely with light changed the way you experience everyday environments? What do you personally notice when you enter a well-lit or poorly lit space?

Yes, absolutely. I notice where the light comes from, where it falls and how it shapes faces, objects and surfaces. I notice contrast, glare, shadows and whether the lighting works with the architecture or competes with it. I also notice whether a space feels welcoming and intuitive, even before I begin to analyse why.

In a well-lit environment, the lighting often appears effortless. It supports what people are doing, helps them understand the space and makes them feel comfortable without demanding attention for itself.

Poor lighting is often immediately apparent. You may struggle to see someone’s face, feel exposed by excessive brightness or become tired because the environment is flat, glaring or disconnected from the time of day. Once you have spent a lifetime studying light, it is difficult to enter a space without observing it – but I still enjoy being surprised by an excellent solution.

When you look back over your career so far, what has kept you curious and enthusiastic about light?

Light is never only one thing. It is science, engineering, architecture, design, biology, psychology and emotion. The more we discover, the more questions emerge.

What has sustained my enthusiasm is the opportunity to work with innovative and creative people from many professions and cultures. Students are particularly valuable in this respect because their questions challenge established assumptions and force us to explain what we think we know.

Above all, I remain motivated by the belief that lighting can add tremendous value to our lives. There will always be more to learn, and more knowledge to share.