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Peter Boyce Ph.D delivers 2017 Trotter Paterson Lecture

On 6th July 2017, the Society of Light and Lighting held the 30th Trotter Paterson Lecture at the Bishopsgate Institute, London. Organised by the Society’s London Events Committee, the keynote speaker was Peter Boyce Ph.D. The lecture was entitled Lighting in Flux.

For many years most interior lighting practice has been based on two objectives, good visual performance without discomfort; two measurement systems, photometry and colorimetry; five metrics, illuminance, illuminance uniformity, colour rendering index, correlated colour temperature and unified glare rating; and one location, the horizontal working plane. Today, nearly all these foundations are being questioned.

In order to explore possible answers to some of the questions surrounding current metrics, Peter began by outlining developments in general understanding of the physiology of the eye and the brain. Peter identified the limitations of photometry in relation to accurately predicting the perception of brightness, colour, off-axis visual performance or circadian stimulation. Going on to suggest two alternatives; the adoption of universal photometry as proposed by Mark Rea, or the potential to abandon photometry and adopt radiometry, acknowledging the potential advantages and drawbacks of both.
Moving on from photometry, Peter then turned his attention to colorimetry and the most widely used metrics for describing light source colour properties, the colour rendering index (CRI) and correlated colour temperature (CCT). As an alternative, Peter looked at the likelihood and potential barriers for the adoption of TM-30-15.

Peter went on to look at alternatives to certain criteria with lighting practice such as unified glare rating (UGR) and illuminance uniformity as well as the assumption that efficient lighting should be delivered to the horizontal working plane. As an alternative, Peter referenced the work of Kit Cuttle, suggesting a move away from the horizontal working plane to focus instead on the perceived adequacy of illumination or the mean room surface exitance (MRSE).

Having identified the current systems, the drawbacks and analysing some of the proposed alternatives, Peter went on to outline evolutionary proposals for the future of lighting practice. Additionally, he paused to reflect upon the developments that have led to the foundations of lighting practice to come under question in the first place. Peter identified a better understanding of the visual and non-visual systems, the development of solid state lighting with its inherent flexibility and the need to find a more extensive justification for lighting to prevent it becoming a simple commodity.

If the primary aims of lighting practice are to achieve good visibility without discomfort, and there are already well-established recommendations to achieve this, Peter highlighted that there is little between lighting systems other than cost. In order to encourage growth and innovation, Peter called for new objectives to be defined, illustrated excellently with ‘Boyce’s Hierarchy of Lighting Needs.’

With regard to lighting needs and the temptation to make claims relating to human-centric lighting, Peter went on to list seven critical questions as a means to assess the validity of such claims.

Having made his conclusions, Peter ended with the adage, we live in interesting times. Peter paid special thanks to Kit Cuttle and Mark Rea and a full list of references can be found here.

The Trotter Paterson Lecture was filmed and footage will be made available shortly.

Peter Boyce is Professor Emeritus at Rensselaer Polytechnic Institute in Troy, New York, USA. He spent most of his career working in the field of lighting. From1966-1990 he was a Research Officer at the Electricity Council Research Centre in England. There, he conducted research on visual fatigue, the influence of age on visual performance, visual problems associated with viewing computer screens, hue discrimination, safe lighting for emergency conditions, and security lighting. 

From 1990–2004 he was Head of Human Factors at the Lighting Research Center at Rensselaer Polytechnic Institute. There, he conducted research on visual performance, visual comfort, circadian effects, emergency lighting, perceptions of safety, and lighting for driving and directed lighting evaluations and product testing.

Since 2008 he has been the Technical Editor of the journal Lighting Research & Technology. He is a Fellow of both the Society of Light and Lighting and of the Illuminating Engineering Society of North America and has received awards from both bodies for his work. He is a recognized authority on the interaction of people and lighting, being the author of the classic text “Human Factors in Lighting”, as well as numerous book chapters, papers and articles.