Invited Speakers

Peter Thorns

V(λ) – Past and Future

The V(λ) spectral luminous efficiency function is the basis for our lighting units, photometry and measurement equipment, and is 100 years old this year. This talk will look at the history behind this fundamental curve, some of the issues with it, and possible future developments.

Peter has worked in Thorn Lighting and Zumtobel Group since 1985 where he has had a number of roles including electronics research and development, manufacturing, software development, photometry, optical design and lighting applications. He is the current Vice-President Standards for the CIE, chair of ISO/TC 274, and is involved in a large number of CEN and BSI committees. He is also involved in the UK Lighting Industry Association and LightingEurope.

Marilyne Andersen

Light exposure in daily urban life – why we should care more

Our exposure to (day)light matters, whether in terms of intensity, timing, spectral distribution or directionality, as it influences a range of human neurophysiological responses. This talk will explore different research directions looking at the impact of the architectural and urban environment we live in on our daily light exposure and, by extension, on our well-being and health.

Marilyne Andersen is a Full Professor at EPFL, where she heads the LIPID lab since 2010. Physicist by training, she specializes in the psycho-physiological effects of (day)light with broader research interests on sustainability in the built environment. She is the co-founder of the startup OCULIGHT dynamics and was previously a professor at MIT for 6 years and Dean of the School of Architecture, Civil and Environmental Engineering at EPFL for 5 years.

Christophe Martinsons

Solid-State Lighting: Health Effects and Knowledge Gaps

In September 2024, the SSLC platform of the 4E implementing agreement of the International Energy Agency published the results of a collective appraisal of the health effects of solid-state lighting. This talk will discuss conclusions and recommendations based on the knowledge gained over the past ten years. Issues that concern both large fractions of the population and small sensitive groups will be addressed, considering acute effects on the eye and the skin, discomfort glare, circadian disruptions, neuro-behavioral effects, effects of temporal light modulation, and long-term effects. Christophe Martinsons is a physicist working in the field of light and lighting at the CSTB in Grenoble, France. He works for governments, public agencies, and municipalities to improve the quality of lighting installations through a careful consideration of environmental impacts and human health effects. He is the president of CIE France, and a recipient of the 2024 Fresnel Medal awarded by the French Lighting Association

Anne Skeldon

Quantitative modelling of the effect of light on human sleep and circadian timing: digital twins for sleep and circadian health?

When we prefer to sleep is inextricably linked to our light environment. So, can we design our light environments such that we wake naturally at the time we need for work or school without recourse to the alarm clock? In this talk, I will discuss current mathematical models of the interaction between light and sleep and circadian timing. Built on well-established physiological principles, these models can capture sleep and circadian timing at an individual level. I’ll discuss how these models can be used to determine the relative contribution of environmental light versus physiological factors to provide personalized guidance on light exposure. I’ll also discuss the opportunities to provide quantitative input for the design of appropriate light environments to reduce sleep and circadian misalignment. Anne Skeldon is Professor of Mathematics at the University of Surrey (UK)

Sylvia Pont Interactions of light with materials – lighting materials and materializing light

Visual perception of materials is crucial for our interactions with the world around us, and understanding the optical and perceptual mechanisms behind it has applications from spectral tuning to holistic appearance tuning. How real materials appear optically is determined by the real light they are in and described by ecological optics. With formal psychophysical experiments we test the perception of their color and texture, how matte/glossy, rough/smooth, hard/soft, glittery, velvety, etcetera we perceive them to be – and how those percepts are related to the ecological optics. I will present a series of studies into light-material-interactions and material perception of computer rendered, real, and painted materials. In addition, I will present research into effects of materials on light, and how materials can be used to make spatial and form-giving qualities of light visible in empty space, using “light probes.” Sylvia Pont is Professor at the Perceptual Intelligence lab, TU Delft