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Newsletter Volume 11. Issue 4. July/August 2018

The Society of Light and Lighting

Part of the Chartered Institution of Building Services Engineers

INSPIRATION AND CONSOLIDATION

New president on future plans

TIME, SPACE AND SPECTACLE

Blurring boundaries with Jason Bruges

Editorial

Secretary Brendan Keely FSLL bkeely@cibse.org SLL Coordinator Juliet Rennie Tel: 020 772 3685 jrennie@cibse.org Editor Jill Entwistle jillentwistle@yahoo.com Communications committee: Gethyn Williams (chairman) Rob Anderson Iain Carlile MSLL Jill Entwistle Chris Fordham MSLL Rebecca Hodge Eliot Horsman MSLL Stewart Langdown MSLL Linda Salamoun MSLL Bruce Weil All contributions are the responsibility of the author, and do not necessarily reflect the views of the society. All contributions are personal, except where attributed to an organisation represented by the author.

Copy date for NL 5 2018 is 20 July Published by The Society of Light and Lighting 222 Balham High Road London SW12 9BS www.sll.org.uk ISSN 1461-524X © 2018 The Society of Light and Lighting The Society of Light and Lighting is part of the Chartered Institution of Building Services Engineers, 222 Balham High Road, London SW12 9BS. Charity registration no 278104

Produced by Unit C, Northfield Point, Cunliffe Drive, Kettering, Northants NN16 9QJ Tel:01536 527297

Printed in UK

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Ossification is always a peril for any venerable and long-lived institution. The invigoration of new blood and new ideas, together with a willingness to embrace rather than reject change, is vital at any time but especially in the teeth of technological and political upheaval.

As new president Iain Carlile pointed out in his address (see p5), one of the strengths of the SLL (and of the lighting profession generally) is the diversity of backgrounds from which its members have emerged. Rather like Jason Bruges (see p9), who works at the intersection of art and hi-tech, the membership of the SLL represents a similar confluence of

creativity and technology. The multiplicity of viewpoints which results from a broad church is essential not only to the health of the society but also to the promotion of good lighting generally. Lighting could, and does, devolve all too easily into a matter of mere quantification and calculation. The bedrock of research and analysis needs to be balanced by an aesthetic approach, the prose tempered by the poetry.

The research aspect was of course very much in evidence at the recent LR&T Symposium where the latest findings on some key areas were presented. In the second of two articles deriving from the event, Prof Arnold Wilkins summarises some of the issues relating to light and the human visual system (see p12). It seems those findings largely endorse what we all know instinctively, that lighting is an elusive, mercurial, natural element and artificial versions are a crude approximation.

‘The human visual system evolved in the natural world and processes natural scenes efficiently,’ says Wilkins. ‘The lighting industry and society at large may take inspiration from the designs in nature,’ he concludes.

Jill Entwistle jillentwistle@yahoo.com

Current SLL lighting guides SLL Lighting Guide 1: The Industrial Environment (2012) SLL Lighting Guide 2: Hospitals and Health Care Buildings (2008) SLL Lighting Guide 4: Sports (2006) SLL Lighting Guide 5: Lighting for Education (2011) SLL Lighting Guide 6: The Exterior Environment (2016) SLL Lighting Guide 7: Office Lighting (2015) SLL Lighting Guide 8: Lighting for Museums and Galleries (2015) SLL Lighting Guide 9: Lighting for Communal Residential Buildings (2013) SLL Lighting Guide 10: Daylighting – a guide for designers (2014) SLL Lighting Guide 11: Surface Reflectance and Colour (2001) SLL Lighting Guide 12: Emergency Lighting Design Guide (2015) SLL Lighting Guide 13: Places of Worship (2014) SLL Lighting Guide 14: Control of Electric Lighting (2016) LATEST SLL Lighting Guide 0: Introduction to Light and Lighting (2017) SLL Lighting Guide 15: Transport Buildings (2017) SLL Lighting Guide 16: Lighting for Stairs (2017) Guide to Limiting Obtrusive Light (2012) Guide to the Lighting of Licensed Premises (2011) Commissioning Code L (2018)

Secretary’s column

‘A line-up of 10 speakers at the top of their lighting fields in one place on one day is a rarity’

Editorial 2 Secretary’s column

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News 4 Strength in members 5 Consideration for the current membership should be balanced with inspiring the next generation, says new president Iain Carlile Ancient and modern The 2018 AGM and Awards

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The art of time and space Chris Fordham talks to Jason Bruges, who marries light, art and cutting-edge technology to create unique installations

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An eye for nature Prof Arnold Wilkins looks at issues affecting the human visual system, based on his LR&T Symposium paper

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Driving forces 15 From dimming strategies to colour quality metrics, Iain Carlile summarises the latest findings from LR&T’s most recently published online papers Events 16

Cover: the lighting scheme by Lighting M Inc for Ota Civic Hall public theatre facility in Ota, Japan, won an Award of Excellence at the 2018 IALD International Lighting Design Awards

Shigeo Ogawa

I’m sure that all those who attended the Lighting Research and Technology Symposium on 16 May and celebrated LR&T’s 50th volume will agree that it was a great event. A line-up of 10 speakers at the top of their lighting fields in one place on one day is a rarity. They all included a short section on their papers published in the first issue of the 50th volume and then spoke about their vision of the future of lighting in their specialist areas. We have approval from many of the speakers to put the presentations on the CIBSE YouTube site and as soon as these are available we will let you know.

Of course 16 May was also the inaugural Unesco International Day of Light and we were joined by many people from all areas of the lighting community. We celebrated the occasion with awards for the LR&T editors and chairs from the past 50 years, as well as a welcome address from CIBSE president and SLL past president Stephen Lisk. Thanks go to Stephen, Liz Peck for her presentation on the legacy of the International Year of Light, and also Geoff Cook, chair of Lighting Research and Technology, who was instrumental in the organisation and delivery of the events.

The AGM was well attended and it was great to welcome the new SLL president, Iain Carlile. Iain’s presidential address is included in this Newsletter (see p5) and can also be found on the website under News and Features. We look forward to working with Iain over the year and thank immediate past president Richard Caple for his sterling work during his year in office. We also thank past president Liz Peck for her work on the Executive as she has now completed her term.

The Lighting Knowledge Series: LightBytes has now finished and we are in the process of developing the next series to take around the UK regions with brand new presentations in the autumn.

We thank the speakers Les Thomas, Oliver Jones and Nick van Tromp from Fagerhult, Helen Loomes from Trilux, Roger Sexton from Xicato and Steve Shackleton, John Cronin and Graeme Shaw from Zumtobel for their work in delivering lighting education to so many members and others over the past year.

We are looking forward to exhibiting at Light Middle East from 23-25 September in Dubai, as well as delivering the third Ready Steady Light ME at the exhibition and conference. Ready Steady Light ME this year will be themed the Year of Zayed, as 2018 marks 100 years since the birth of the late Sheikh Zayed bin Sultan Al Nahyan, the founding father of the UAE, who died in 2004. We’re very interested to see how the teams interpret the theme and look forward to working again with Dubai-based lighting design studio Light.Func on the event, and on their Lighti.cation project (an initiative with local students and universities to encourage mentorship within the lighting design community).

We hope to meet with many existing SLL and CIBSE members in the region, as well as welcoming new members.

As our event and committee year comes to a close both myself and my colleague Juliet Rennie thank all the SLL volunteer members for their valuable time and efforts in progressing the society’s operations. We’ll be back in touch in September and anticipate another brilliant year.

In the meantime, if there is anything we can help you with please do get in touch.

Contents

Brendan Keely bkeely@cibse.org For up-to-date information follow us on Twitter @sll100

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CIBSE must speed up response to change, says new president Incoming CIBSE president Stephen Lisk has called for the institution to accelerate its response to a rapidly changing world.

The former president of the SLL focused on the pace of change within the natural world, as well as the construction sector and the regulatory climate in which it operates. His address stressed the vital importance of education and expert guidance to ensure that the built environment provides positive spaces for living and working into the future.

A major theme for Lisk’s year in office as CIBSE president will be the importance of collaboration between all the professionals whose experience should influence the design of buildings.

It is in such collaboration that Lisk sees the value and relevance of a professional organisation such as

On the lighter side...

Anyone acquainted with the TV series Pimp My Ride will be familiar with the principle, but who knew this was a thing among Japanese truck drivers? Some 600 of them make up the charitable, Utamaro-Kai association of dekotora – decorative – drivers.

Their extravagantly decked-out cabs invariably include flamboyant light fittings such as chandeliers, while the exterior of the vehicles is

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CIBSE: constructive debate between like-minded professionals producing the most comprehensive and practical solutions to building design challenges.

He also stressed the importance of communicating the institution’s expertise, commending the CIBSE Knowledge Portal and Build2Perform Live as excellent examples of initiatives that increase accessibility and fulfil the body’s aim of sharing its knowledge.

Lisk was concerned to continue and accelerate the pace of change within CIBSE, building ‘a virtuous circle of competency’. Members and, critically, the huge number of participants in CIBSE’s special interest groups who are not members, should be prepared for radical new thinking in the way the institution engages with and consults its unique corps of expert contributors, said Lisk.

Originally from New Zealand, Lisk has 30 years’ experience in lighting, ultimately establishing his Bristol-based lighting studio One Eighty Light.

emblazoned with lights. The idea began in the 1970s, when movies such as Torakku Yaro (truck rascals) featured eccentric, dekotora-driving heroes. Japanese drivers began decorating their own trucks in hope of being cast in the movies, before it evolved into a fundraising body.

Photographer Todd Antony (www. toddantony.com) has captured several of them. ‘The truck designs can be quite personal to each driver and can cost anywhere up to and over $100,000,’ he says.

Jonathan Speirs fund awards two winners The 2017/18 Jonathan Speirs Scholarship Fund award has gone to two winners, Katie Corr (top right), a Master’s student at Queen’s University, Belfast, and Azadeh Omidfar Sawyer (left), a PhD student at the University of Michigan.

Corr’s interest lies in rediscovering what she describes as the ‘alchemy of light’, an understanding of how light evokes mood and influences the experience of space, something she feels has been lost in our obsession with light levels and performance.

Sawyer’s studies focus on how we can improve our approach to daylighting design, balancing occupant comfort and interest with sustainability concerns.

Task group investigates circadian entrainment Mark Rea, professor of Architecture and Cognitive Sciences at the Lighting Research Center (LRC), is to chair a task group examining the use of lighting to support the circadian entrainment of people in daytime work environments.

The initiative has been launched by Illinois-based Underwriters Laboratories (UL), the world’s largest independent, not-for-profit testing laboratory.

The aim is to develop a recommended practice for the specification, measurement and application of lighting to support circadian entrainment.

‘Lighting isn’t just for vision any more,’ said Dr Rea. ‘It’s high time we had a valid, agreed-upon metric and some basic guidelines so that healthy lighting can be effectively delivered to benefit society.’

The task group will seek input from design professionals, manufacturers, facility owners and scientists. It will review proposals being considered, vote on the technical merits of each recommendation, and draft the recommended practice.

The target date for publication of the recommended practice is May 2019.

AGM: Presidential address

Strength in members

‘One of the key strengths of the society is its members and the diverse range of backgrounds and careers that they represent’

Promoting lighting as a career and inspiring the next generation of lighters through initiatives such as Stem was a major priority, said new president Iain Carlile in his address. He wanted to build on the work of the previous two presidents, Jeff Shaw and Richard Caple in this respect, he said. ‘I am pleased to say that out of the legacy of Night of Heritage Light, we are looking at how we can implement the schools engagement programme Pockets of Light with the support of the SLL regional lighting representatives across the regions.’

His own pathway to lighting, like many other practitioners, had not been a straightforward one, said Carlile, and he regarded this typical diversity in the profession as an advantage.

‘I believe one of the key strengths of the society is its members and the diverse range of backgrounds and careers that they represent,’ he said. ‘As it says on the SLL website, “the SLL welcomes all those who are interested in any aspect of the world of light, lighting and its applications.

Lighting designers, consulting engineers, researchers, students, professors, manufacturers, sales staff; all contribute and all are members of the SLL”.’

This inclusivity is what originally attracted him to the society as his professional body of choice, he said, and he wanted to further encourage the different and highly individual contributions people could make. ‘I have on many occasions discussed the benefits of being a member of the SLL with people who, while working within the field of lighting with years of relevant experience, did not see themselves as being eligible to join, believing they did not have the right credentials to do so.’

One of his aims would be to reach out to these individuals and groups, dispelling any misconceptions and reinforcing what the society could do for them, and how they might become involved in its activities.

The society continues to grow, he said, and currently has more than 4000 members, all at various grades of membership, and everyone wanted to see continued expansion. However, it was also crucial to safeguard the interests of the current membership, he said.

‘While encouraging future generations in lighting as a career, and looking at how we attract new members within the immediate profession and further afield, is something I would like to progress during my year as president, more importantly, we need to continue to support our existing members and ensure that the society stays relevant to their needs,’ he said.

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Inspiring the next generation must be balanced with care for the current constituency, says Iain Carlile in his address

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AGM: Presidential address

How Iain Carlile became a lighting professional and SLL president

‘I would like to review what the society offers, and to find out what our members want from us – and even offer some things that they do not yet know they want’ ‘We must continue to offer our members the tools to help progress in their careers, achieve professional recognition and hopefully have a bit of fun along the way.’

Carlile acknowledged that the task was made more difficult with rapidly changing technology not only having an effect on light sources, luminaires and controls, but also in the methods used to communicate, disseminate and deliver information.

‘To that end as part of my year I would like to review what the society offers, how this is delivered and to find out what our members want from us – and hopefully even offer some things that they do not yet know they want.’

Achieving these aims was a team effort, he said. ‘Thankfully I can draw on the combined knowledge and experience of many talented members of the society who all volunteer their time to its work, be this in the activities of various committees and boards, writing guides, organising events, or getting the word out to the regions.’ As chair of the Regional Lighting Representatives Committee this past year he said he had been ‘extremely impressed’ by the hard work of the regions and the degree of engagement at a local level.

Fulfilling all of these aims meant that a wider objective could be achieved, concluded Carlile, ‘promoting the message of good lighting to a wider audience, for the benefit of all’.

Summary of objectives To review what the SLL does, and how we engage with our membership, ensuring we stay relevant to our existing members in their professional activities, now and in the future To appeal to the wider lighting community, attracting new members and raising the SLL’s profile To continue past presidents’ work on lighting career pathways and Stem, encouraging future generations of lighters

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‘While having an interest in light from an early age, playing with prisms, lamps and LEDs in science classes, like most, I was not aware of a potential career in lighting. Driven by a love of Lego, Doctor Who, the A-Team, science fiction and Airfix kits (geek status confirmed), I pursued mostly science, technology and maths-related subjects at school, although I did also dabble in the arts, through the study of drama.

It was during the study of drama, through assisting with the stage lighting for a number of school plays, that I gained my first appreciation of the ability of light to create different moods, effects and to facilitate tasks.

My interest in the application of light had been sparked…

With Doctor Who having been cancelled in 1989 I realised I would never be the next Doctor and on completion of my GCSEs decided to take the path of engineering-related subjects for my A-levels.

As a teenager, having a Saturday job in the local BHS lighting department ended up with me advising customers on the application of decorative lighting, choice of bulbs, as I called them then, and even helping them with the lighting layouts in their homes.

A further interest in lighting had been kindled…

It was during my holidays from my undergraduate electronic engineering course that I worked for TDP, a small building services engineering consultancy in Swindon, where I worked under an engineer called David Moore, who was passionate about light and its many applications. I was immediately hooked; to me lighting was the part of the built environment that could instantly have an effect on people’s appreciation and comfort of a space.

My spark of interest in lighting had turned into a raging fire and I wanted to know more about all aspects of light. It was at this time that I was first introduced to CIBSE and the SLL; the then code for lighting (1994 edition) permanently sat on my desk.

After graduating I began a career in building services engineering with WhitbyBird Engineers, furthering my passion for light, embarking on the Light and Lighting Masters degree at UCL, and eventually moving to dpa lighting consultants.

Around this time I attended the SLL Conference in Dublin in 2004 and was bowled over by the passion and dedication of the community of lighters attending.

When during the conference Mike Simpson asked me if I would like to get more involved with the activities of the society, I instantly said yes.

Since then I have sat on the Newsletter committee, later to become the marketing and communications committee, which I myself chaired at one point, along with being a member of the LR&T journal editorial board, various sub-committees, and in more recent years the SLL Council and SLL Executive.’

AGM: Awards

Ancient and modern

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Livery Halls are generally historic affairs but the Haberdashers’ Hall in London’s West Smithfield, venue for this year’s AGM, is something of an exception. Designed by Sir Michael Hopkins, Haberdashers’ Hall is one of the newest buildings, housing one of the oldest of the Livery Companies (14th century), and combining modern architecture with state of the art technology.

There were two Honorary Fellowships, for Peter Boyce and Graham Phillips. ‘A very worthy recipient’, said Peter Raynham in his citation for Boyce, admitting it was impossible to do full justice to his ‘long and productive career’.

Boyce started work in 1966 at the Electricity Council Research centre in Capenhurst, near Chester, joining the IES soon after. During the time he worked there, until 1990, he published 25 papers in LR&T; led the task group for the 1984 Code of Lighting; published the first edition of Human Factors in Lighting (1980) and was chair of what was then the CIBSE Lighting Division from 1986-7.

In 1990 he went to work at the Lighting Research Center at Rensselaer Polytechnic Institute, returning to the UK in 2004.

His research career has encompassed various aspects of visual performance, emergency lighting and circadian effects.

‘I have not been able to work out how many papers he has written,’ said Raynham, ‘but it runs into the hundreds.’

He has been chair of the technical and publications committee at different times over the years, wrote the majority of the SLL Handbook and contributed to the SLL Code in 2012, and has been technical editor of LR&T since 2008. A Fellow of the SLL and IESNA, in 2003 he was awarded the IESNA Gold Medal and last year was Lux Person of the Year.

Graham Phillips was secretary of the CIBSE Daylight Group for 14 years, from 2001 until 2015. Born in 1938, Phillips took a circuitous path to a lighting career, first reading geology, with physics and maths at Exeter University, followed by geophysics at Birmingham University. He then took a two-year course sponsored by the London Master Builders Association which led to membership of the Chartered Institute of Building.

He took on an assistant lectureship in Building Science at Chelmsford Technical College, now Anglia Ruskin University.

In 1967 he transferred to North East Surrey College of Technology (Nescot) as a lecturer in building and environmental science where he specialised in both lighting and acoustics, setting up large laboratories for both.

In 1976 he embarked on a two-year part-time MSc in environmental science – architectural engineering and design – at the Bartlett. He contributed the sections on electric lighting and daylighting to Environmental Science by Brian Smith and Mary Sweeney, published in 1983. In 1986 he was seconded to BRE for a year to work with Dr Paul Littlefair. He also joined the CIE-UK committee.

After retiring from full-time senior lectureship at Nescot in 1999, he continued some part-time work there. He was also drawn in to Mike Wilson’s Low Energy Architectural Research

Photography by Michael Eleftheriades

This year’s setting for the AGM and Awards reflected both past and future

From top: Peter Boyce (left) with outgoing president Richard Caple; Graham Phillips (left); Kit Cuttle (on video)

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Unit at London Metropolitan University. He was awarded the CIBSE Bronze Medal for Services to the Daylight Group in 2016.

‘It was under Graham’s stewardship that attendance at Daylight Group meetings steadily increased to, occasionally, over a hundred,’ said John Mardaljevich in his citation. ‘I recall in particular one meeting in 2014 hosted by Atkins at their Epsom offices where there was standing room only.’

The Lighting Award was given to Kit Cuttle. ‘It is often said that lighting is both an art and a science but few of its practitioners manage to cover both of these extremes,’ said Peter Boyce in his citation. ‘Kit Cuttle is one who does.’

Cuttle began in lighting by joining the manufacturer Falk, Stadelmann and Co. After several years, and having joined the IES in 1959, he moved to Derek Philips Associates, then the only independent architectural lighting consultant practice in the UK. He then moved to Pilkington Brothers where he became involved with daylighting and worked with Joe Lynes.

During this time he undertook a master’s degree under the supervision of James Bell at the University of Manchester.

Cuttle eventually left Pilkingtons, moving to New Zealand, and into education. He has taught lighting at the Victoria University of Wellington, the Lighting Research Center at Rensselaer Polytechnic Institute and the University of Auckland, as well as contributing to courses in Australia and Hong Kong. ‘Many students have benefited from his expertise in calculation, his insistence on precision in measurement and his eye for how lighting affects perception,’ said Boyce. ‘There is one consistent theme running through his career – the need for lighting to move beyond the illuminance on the horizontal working plane.’

His first attempt to move in this direction was the Multiple Criterion Design Method, an innovative and quantitative approach to lighting design published by the IES in 1977.

Over the past decade he has published a series of books and papers advocating how lighting design can be based on perception. His latest book, Lighting Design: A Perception Based Approach, brings together many of his ideas. He was recently awarded a doctorate by Dublin Institute of Technology at the age of 80.

‘It should be clear that Kit Cuttle’s contribution to lighting has been immense,’ said Boyce. ‘He is unstinting with his time, always thoughtful and engaging with both student and colleague, willing to listen to argument, and free of the sin of arrogance. He is a very worthy recipient of the SLL Lighting Award.’

The winner of this year’s Regional Award was Manny Stone, technical manager at Marlow Integrated Designs and former chair of Home Counties North West region.

The Leon Gaster Award went to Kees Teunissen for his paper, Characterising User Preference for White LED Light Sources with CIE Colour Rendering Index Combined with a Relative Gamut Area Index. The Walsh Weston Award was given to Ling Xia for his papers, Light Diffuseness Metric Parts One and Two. LET Diploma in Lighting recipients were also presented with their certificates.

Celebrating the 50th volume this year, there have been a series of LR&T Awards, recognising both editors and secretaries/chairs. Some were handed out at the recent LR&T Symposium and the remainder at the AGM. Those honoured were Henry Swinburne, David Loe, Jacqueline Balian, Ron Simons, David Carter, Barry Copping and Peter Boyce.

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Photography by Michael Eleftheriades

AGM: Awards

From top: Manny Stone (left); Henry Swinburne; Les Thomas, Helen Loomes and Roger Sexton of Sponsors in Partnership Fagerhult, Trilux and Xicato respectively

The art of time and space Jason Bruges, whose extraordinary mixed-media installations sit at the intersection of art, technology and design, talks to Chris Fordham In a changing world where the boundaries between art, technology and architecture are becoming ever more blurred, Jason Bruges lives at their intersection. At his art and design studio in Hackney, East London, he and his multidisciplinary team have been responsible for a number of exceptional national and international projects over the past 16 years, working with different media in which light is frequently a significant component. An undoubted pioneer in his field, his work as he describes it ‘blends architecture with interaction design and uses a hi-tech, mixed-media palette to explore spectacle, time-based interventions and dynamic spatial experiences’.

Among his better-known UK installations are the New Year’s beacon for The Shard; digital, interactive wallpaper at Great Ormond Street Hospital; the Showtime facade of the W Hotel in Leicester Square, and Platform 5 at Sunderland Station, a 144m-long work which conjured up an extraordinary virtual platform with shadowy moving figures.

His approach to design, you might speculate, was informed by the fact that he comes from a family with both creative and technical influences: his mother was an artist and his father a computer programmer.

He trained as an architect at Oxford Brookes University and the Bartlett School of Architecture at UCL. He worked with Foster and Partners for three years before moving to Imagination to become a senior interaction designer.

While studying at UCL he became involved in a research group working in cybernetics and robotics, which gave him the knowledge to apply his particular blend of hi-tech design and art. He set up his own studio in 2002.

When it comes to working with light as a medium, Bruges says that he is quite often ‘responding to phenomena that exist in nature and the world around us’. For him, algorithms

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One of the studio’s most recent projects was an ambitious series of robotic light/shadow/sound installations – Where Do We Go From Here? – which marked Hull’s City of Culture year in 2017

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and behaviour are just as interesting as how something looks. ‘There are a lot of technologies that we explore and interrogate, hack, reuse in different ways – light is a good shorthand to describe a lot of them, giving dynamism and movement, something that allows us to create a narrative, a technology-art hybrid.’

A striking example of this is Dichroic Blossom where Jason Bruges Studio has interpreted the Chinese plum blossom, or meihua, one of the most beloved flowers in China. A permanent, large-scale wall installation created in 2014 for the Beijing Guo Real Estate Development Company, it is an interactive feature that changes appearance according to different times of the day, the different seasons, and the

‘Light is a good shorthand to describe a lot of technologies... giving dynamism and movement, something that allows us to create a narrative, a technology-art hybrid’

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varying activities in and around the multifunction hall. Clusters of LEDs and prisms form an intricate network of dichroic wall sculptures, reflecting and refracting the light as they ascend across the wall, branching out as they progress skyward. The organic growth effect is dependent on an algorithm which considers the number of people standing next to the wall, their proximity, dwell time and grouping.

One of the more interesting elements of this project for Bruges was the way in which the studio married the work carried out in China (it was there that the prisms were manufactured) with elements built in the UK studio. LEDs were supplied by Mike Stoane Lighting and the studio was commissioned as a collaborator with Foster and Partners.

One of the studio’s largest projects in terms of scale, and perhaps the design with the greatest public and media exposure, was the commission to create a beacon installation for The Shard that acted as a countdown device for Londoners on New Year’s Eve 2014. Working alongside LED luminaire specialist SGM Light and services company Resource Group, the team had the spire and 40 storeys of the 70-storey building to play with. Altogether nine truckloads of equipment were used to create Shard Lights, a dynamic piece of public art designed to reflect and evoke the spirit and energy of the city. The concept included back projection into a mist within the spire, producing a dynamic coloured light canvas on the facade, and involved the world’s first IP-rated moving-head

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LED luminaire. The beacon was used in the lead up to New Year’s Eve in a groundbreaking nightly event. On the night itself the countdown was created by a giant pixelated numeric supergraphic, synced to London’s world-famous fireworks display, creating Western Europe’s highest art installation.

The breadth of the studio’s work is impressive. Bruges is always interested in creating spectacle, engaging with people, and interfacing with the building where he can. Projects are both designed and built within the studio so his team has a variety of skill sets, coming from a plethora of backgrounds: architects, artists, lighting designers, industrial designers and visualisers, as well as specialists in electronics, programming and project management.

Most of the studio’s work is permanent but they also have projects that are temporary, such as the spectacular lighting installation, Light Masonry, in the nave of York Minster for the 2016 Illuminating York event. The design was inspired by the ‘continuous crafting and iterating of layers of work’ created by the minster’s stonemasons, and the result is a dynamic ‘synchronised procession of light that highlights and explores the nave as a choreographed architectural experience’. The installation was constructed from a bespoke system of 48 computer-controlled Icon Beam moving-head luminaires. It won a D&D award in 2017.

Scent Constellation, also installed in 2016 in the Le Grand Musée du Parfum in Paris, is a sound and light artwork in which the visual spectacle and message are married together seamlessly with the narrative design. It is a highly innovative way to purvey the story of perfume, literally conveying its essence. A laser creates crisp lines of light that refract off prisms representing the 200 ingredients that are used for the five classic perfume typologies: eau de cologne, oriental, fougères, florale and chypre.

‘An algorithm generates a network of traced lines of light, which scribe via prisms to create crystalline-like facets that represent the mathematical relationships between the ingredients,’ says Bruges. ‘The soundscape is created from a library of sounds developed in response to the scent families, and representative of the stability and duration of the raw materials as they are mixed for the final perfume composition.’

Among his most recent projects are the Pentagonal Portal and Experience Tunnel at King’s Cross, and an ambitious series of robotic light/shadow/sound installations – Where Do We Go From Here? – to mark Hull’s City of Culture year in 2017. In all 20 6m-tall industrial robots performed a series of idiosyncratic light ballets in four locations in the old town.

Bruges doesn’t like to pigeonhole his company as one thing or another, encompassing as it does such a broad spectrum of disciplines. The beauty and strength of his work is not just in the visual, but how he manages to interweave the context into pieces in an interesting and engaging manner. There is a thoughtfulness and rationale to his works that gives them complexity, depth of meaning and a multi-layered appeal.

Top left: Dichroic Blossom (detail left) large-scale, interactive wall installation. Bottom left: Light Masonry at York Minster, part of the 2016 Illuminating York event. Right, from top: Scent Constellation (detail centre) at Le Grand Musée du Parfum in Paris and Shard Lights, which counted down to the New Year in 2015

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LR&T Symposium

An eye for nature Summarising his recent paper delivered at the LR&T Symposium, Prof Arnold J Wilkins looks at recent research into the impact of issues such as flicker and colour contrast on the human visual system The human visual system evolved in the natural world and processes natural scenes efficiently. The natural world has little flicker, few repetitive contours and modest colour contrast.

When lighting is unnatural, however, it results in inefficient neural processing and this in turn leads to discomfort.

Flicker

A simulation of the phantom array

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In the natural world flicker results mainly from light reflected from the surface of water or interrupted by the branches of trees. It is never regular and continuous. In the urban environment it is difficult to avoid regular continuous flicker from electric lighting. The flicker is seldom visible, although when it is, it constitutes a potential hazard. The visibility of flicker varies with frequency. It is maximal at about 20Hz, and minimal above 60Hz (see graph opposite). This graph also shows the effects of frequency on the visibility of illusions of colour evoked by flicker, and the percentage of individuals with photosensitive epilepsy who are liable to seizures.1 Flicker from fluorescent lighting with a magnetic ballast is not usually visible. It is nevertheless resolved by the human retina, disturbs the control of human eye movements, causes headaches and impairs visual performance.2 The flicker is above the critical flicker fusion threshold, CFF. The CFF is measured with diffuse flicker during steady gaze that avoids large rapid eye movements (saccades). These viewing conditions are atypical because we make two or three saccades every second, and some of these are large. When they are large they are fast, with velocities of up to 700 degrees a second. The scene we look at is rarely uniform but contains many contours, and these contours are swept across the retina with each saccade. Under lighting that repetitively fluctuates in brightness, the contours form a repetitive pattern, known as the phantom array. This intra-saccadic pattern is rarely visible, largely because it is masked by the images before and after the saccade. When these have few contours, as at night, the phantom array can become intrusive, for example when the LED tail-lights of cars appear in a striped pattern3 (see left).

We have measured the visibility of the phantom array as a function of the contrast of the flicker. For flicker at 100Hz or 120Hz the array becomes visible when the Michelson contrast (essentially, the difference between maximum and minimum luminance) exceeds around 15 per cent. Incandescent lighting, which is rarely associated with complaints, has a contrast less than this. Fluorescent lighting with magnetic ballasts, which was often associated with complaints, has a contrast that is greater than 15 per cent. The phantom array provides for a repetitive spatial pattern during a saccade. When present in text, repetitive spatial patterns are known to impair reading

LR&T Symposium

by interfering with the appropriate realignment of the eyes following each saccade.4,5 There is therefore a potential mechanism whereby the phantom array might impair reading.

Repetitive patterns of stripes at low contrast can most readily be seen when their spatial frequency is around three cycles per degree subtended at the eye.6 For a 10-degree saccade, with a velocity of around 300 degrees per second, the phantom array should therefore be most visible with flicker at about 1kHz. We have measured the visibility of the phantom array as a function of the contrast of the flicker and it increases progressively from 100Hz to 300Hz, as expected. The upper limit of perception of the array should be at around 10kHz when its spatial frequency is close to the acuity limit for gratings. We have recorded the array with bright narrow stimuli, and it is visible at a limit of 10kHz in some observers, although many observers have a lower threshold frequency.

‘It is difficult to avoid regular continuous flicker from electric lighting. It is seldom visible but constitutes a potential hazard’

Repetitive patterns

Visibility of diffuse flicker, percentage of trials with illusions of colour, and percentage of patients with photosensitive epilepsy showing photoparoxysmal EEG response (seizure susceptibility)

shapes. For all categories of image, the discomfort was minimal for those images with a 1/f Fourier amplitude spectrum.

Penacchio and Wilkins14 developed a simple algorithm that measured the extent to which the Fourier amplitude of the images approximated that of images found in nature. A cone with a slope of 1/f was fitted to the two-dimensional Fourier amplitude spectrum, and the residuals (errors) were weighted by a contrast sensitivity function gleaned from the literature.

The algorithm had no free parameters but it was well able to predict observers’ ratings of visual discomfort. (The algorithm accounted for more than 25 per cent of the variance in observers’ ratings.) It has also been shown to predict the size of the cortical haemodynamic response to images.15

t

The visual system has adapted to process natural images and these images have a Fourier amplitude spectrum (in simple terms, a way of measuring brightness at different spatial scales) close to 1/f.8,9 The human contrast sensitivity function is optimised for encoding images with this structure, as are the receptive fields of neurons in the primary visual cortex,10 which produce a sparse cortical response, thereby reducing metabolic demand.9 In computational models of the visual system, striped patterns, which are rare in nature and do not conform to a 1/f amplitude spectrum, result in an excess of ‘neural activity’ and a non-sparse distribution of ‘neural’ firing.11 Wilkins3 reviewed neuroimaging studies and concluded that images that are uncomfortable to observe are generally associated with an elevated cortical haemodynamic response (the mechanism that allows the rapid delivery of blood to active neuronal tissues). Further, individuals who are susceptible to discomfort exhibit a larger haemodynamic response than those who are not. Both findings are consistent with the view that discomfort is a homeostatic mechanism that avoids excessive cerebral metabolism.

The above suggests that images are processed inefficiently by the brain if they are unnatural, do not have a 1/f amplitude spectrum, and in consequence are uncomfortable to look at.

Juricevic12 and others13 asked observers to rate the discomfort from images of modern art and of filtered visual noise or

In many lighting installations the spatial arrangement of luminaires is repetitive and uncomfortable

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LR&T Symposium

An example of a classroom with high colour contrast (left) and with saturation decreased (right), reducing contrast

In many lighting installations the spatial arrangement of luminaires is repetitive and uncomfortable (see previous page). There are many examples.

Colour

The use of high colour contrast is rare in nature. Repetitive coloured patterns can evoke discomfort and a large cortical haemodynamic response, and they do so in proportion to the difference in the chromaticity of the component colours.16 Many environments, particularly in primary schools, feature material with high colour contrast (see above). This is also true of much advertising and electronic material, and is particularly evident in videos for children.

In summary, the lighting industry and society at large may take inspiration from the designs in nature.

Arnold J Wilkins is professor emeritus at the Department of Psychology, University of Essex. This article is based on his paper, Illumination from Darwin and Discomfort from Illumination, which was delivered at the LR&T Symposium on 16 May and subsequently at LS16 at Sheffield University in June.

LR&T Symposium programme The where and what of lighting vision research: Mark Rea Daylighting buildings: John Mardaljevic Light sources and luminaires: Peter Thorns

1 AJ Wilkins, Wilkins 1994 Visual Stress.pdf, Visual Stress, vol Oxford Psy, no 24. 1995 2 A Wilkins, J Veitch and B Lehman, LED lighting flicker and potential health concerns: IEEE standard PAR1789 update. 2010 IEEE Energy Conversion Congress and Exposition, ECCE 2010 – Proceedings, 2010 3 AJ Wilkins, A physiological basis for visual discomfort: Application in lighting design. LR&T Vol 48, no 1, 2016 4 AJ Wilkins et al, Stripes within words affect reading. Perception, Vol 36, no 12, 2007 5 S Jainta, W Jaschinski and AJ Wilkins, Periodic letter strokes within a word affect fixation disparity during reading. J Vis, Vol 10, no 13, 2010 6 FW Campbell and JG Robson, Application of Fourier analysis to the visibility of gratings. J Physiol, Vol 197, no 3, pp 551–566, 1968 7 X Troncoso, J Otero-Millan, S Macknik, I Serrano-Pedraza, and S Martinez-Conde, Saccades and microsaccades during visual fixation, exploration, and search: Foundations for a common saccadic generator, J Vis, Vol 9, no 8, pp 447–447, 2010 8 DJ Graham and DJ Field, Statistical regularities of art images and natural scenes: spectra, sparseness and nonlinearities. Spat Vis, Vol 21, no 1–2, pp 149–164, 2007 9 B Olshausen and DJ Field, Sparse coding with an incomplete basis set: a strategy employed by V1, Vision Research, Vol. 37, no 23. pp 3311–3325, 1997 10 JJ Atick and AN Redlich, What does the retina know about natural scenes?, Neural Comput, Vol 4, no 2, pp 196–210, 1992

Architectural lighting design: Kevin Mansfield

11 PB Hibbard and LO Hare, Uncomfortable images produce non-sparse

Non-visual effects of light: Mariana Figueiro

responses in a model of primary visual cortex, 2014

Visual discomfort indoors: Arnold Wilkins

12 I Juricevic, L Land, A Wilkins and MA Webster, Visual discomfort and

Lighting controls: John Aston Road lighting: Steve Fotios Plus two keynote presentations on lighting fundamentals

by Mike Simpson and Peter Boyce The full papers by the speakers are available in Issue 1 of LR&T Vol 50 (www.cibse.org/Knowledge/Online-Access).

Many of the presentations will be available on the CIBSE YouTube site. Email jrennie@cibse.org for details

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References

@sll100

natural image statistics, Perception, Vol 39, no 7, 2010 13 D Fernandez and AJ Wilkins, Uncomfortable images in art and nature, Perception, Vol. 37, no 7, 2008 14 O Penacchio and AJ Wilkins, Visual discomfort and the spatial distribution of Fourier energy, Vision Res, Vol 108, 2015 15 ATD Le et al, Discomfort from urban scenes: Metabolic consequences, Landsc. Urban Plan, Vol 160, 2017 16 SM Haigh et al, Discomfort and the cortical haemodynamic response to coloured gratings, Vision Res, Vol 89, 2013

LR&T essentials

Driving forces From dimming strategies to colour quality metrics, the latest LR&T online papers examine human preferences, discovers Iain Carlile With smart-lighting technology now readily available in the consumer market, Juric and Lindenmeier have investigated the drivers and consequences of consumer resistance to adoption of the technology.

An initial study was undertaken with a sample size of 653 German consumers, from which empirical results suggested performance, social pressure, compatibility and health concerns were all major drivers of consumer behaviour.

A follow-up study of 115 participants investigated health concerns more closely.

The results of the studies showed that health-related concerns and pricing issues were the major inhibitors of consumer resistance to adoption of innovative smart-lighting products. In addition, differences were found in gender and age groups, with younger male consumers more inclined towards smart lighting products than female and older consumers.

Turning to the use of controls, Chraibi et al look at users’ experiences in open-plan office spaces where dimming strategies are used to provide energy savings while also providing suitable levels of light for task within occupied areas.

While greater energy savings can be achieved through zone and desk-based dimming, the comfort of other occupiers of the space may be affected.

An experiment was therefore conducted in a mock-up office to investigate the effect of different dimming speeds on colleagues experiencing changes triggered by others. A total of 17 participants aged between 30 and 55 years old took part in the experiment, all evaluating changes in the office lighting conditions for their noticeability and acceptability.

The study showed that faster fade times increased the noticeability of changes due to dimming caused by the action of a colleague, while a fade time of two seconds was considered acceptable by more than 70 per cent of the participants.

Esposito and Houser looked at the use of IES TM-30-15, conducting an experiment to review colour quality over different spectral power distributions. They selected a total of 24 different spectra with systematic variation in average fidelity (IES Rf), average gamut (IES Rg) and gamut shape at a neutral white colour temperature of 3500K. Twenty participants rated a set of objects along a continuous scale for naturalness, preference, vividness and skin preference.

From the results of the experiment it was found that the highest-rated spectra all had an average gamut greater than or equal to 100 (IES Rg ≥ 100) and did not desaturate red hues (IES Rcs,h16 ≥ 0%).

The authors note that since spectra with the same average fidelity and gamut area can elicit different perceptual responses, a two-metric system of colour rendition, comprising average metrics for fidelity and gamut, cannot fully describe colour quality alone. They therefore recommend the need for a colour rendering graphic such as the IES Colour Vector Graphic for any design scenario where colour rendering is of even modest importance.

Iain Carlile, MSLL, is an associate of DPA Lighting

Lighting Research and Technology: OnlineFirst In advance of being published in the print version of Lighting Research and Technology (LR&T), all papers accepted for publishing are available online. SLL members can gain access to these papers via the SLL website (www.sll.org.uk) An empirical analysis of consumer resistance to smart-lighting products J Juric and J Lindenmeier Dimming strategies for open office lighting: User experience and acceptance S Chraibi, P Creemers, C Rosenkötter, EJ van Loenen, MBC Aries and ALP Rosemann

From an experiment to review colour quality over a range of spectral power distributions (T Esposito and K Houser)

Models of colour quality over a wide range of spectral power distributions T Esposito and K Houser

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EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS...EVENTS

2018 4 July CIBSE training: Emergency Lighting to Comply with Fire Safety Requirements Venue: CIBSE, Balham, SW12 training@cibse.org 12 July Fundamental LED Course (organised by the ILP) Venue: ILP, Regent House, Rugby jo@theilp.org.uk 17 July CIBSE training: Energy Efficiency Building Regulations Part L Venue: CIBSE, Balham, SW12 training@cibse.org 3-5 September Shanghai International Lighting Fair Venue: Shanghai New International Expo Centre (SNIEC) http://shanghai-international-lighting-fair. hk.messefrankfurt.com/ 13-14 September Symposium on Promotion and Protection of the Night Sky Location: Capraia Island, Italy http://capraianightsky2018.com 17-21 September Exterior Lighting Diploma Module A (organised by the ILP) Venue: Draycote Hotel, Rugby angela@theilp.org.uk 19 September How to be Brilliant (organised by the ILP) Venue: Body and Soul, London EC1 jess@theilp.org.uk 23-25 September Light Middle East (including Ready Steady Light ME with the SLL and Light Middle East Awards) Venue: Dubai International Convention and Exhibition Centre www.lightme.net 25-27 September Trends in Lighting Conference/Exhibition Venue: Opera House, Bregenz, Austria www.trends.lighting

23-25 September: Light Middle East, Dubai, including Ready Steady Light ME

4 October CIBSE training: Lighting Design Principles and Application Venue: CIBSE, Balham, SW12 training@cibse.org

Lighting Knowledge Series: LightBytes The Lighting Knowledge Series is kindly sponsored by Fagerhult, Trilux, Xicato and Zumtobel. For venues and booking details: www.sll.org.uk

5 October CIBSE training: Emergency Lighting to Comply with Fire Safety Requirements Venue: CIBSE, Balham, SW12 training@cibse.org 8-12 October Exterior Lighting Diploma Module B (organised by the ILP) Venue: Draycote Hotel, Rugby angela@theilp.org.uk 17 October How to be Brilliant Venue: Body and Soul, London EC1 jess@theilp.org.uk 25-27 October Professional Lighting Design Conference Venue: Marina Bay Sands, Singapore https://pld-c.com 6-9 November Interlight Moscow Venue: IEC Expo Centre, Moscow https://interlight-moscow. ru.messefrankfurt.com/

26 September Lighting for Health and Wellbeing Venue: Cavendish Conference Centre, W1 http://lightingforhealthandwellbeing.com

7 November Fundamental Lighting Course (organised by the ILP) Venue: ILP, Regent House, Rugby jo@theilp.org.uk

3 October CIBSE training: Lighting – Legislation and Energy Efficiency Venue: CIBSE, Balham, SW12 training@cibse.org

14-15 November LuxLive (including SLL Young Lighter of the Year) Venue: ExCel London http://luxlive.co.uk

LET Diploma: advanced qualification by distance learning. Details from www.lightingeducationtrust.org or email LET@cibse.org CIBSE Training: various courses across the whole spectrum of lighting and at sites across the UK. Full details at www.cibse. org/training-events/cibse-cpd-training LIA courses: details from Sarah Lavell, 01952 290905, or email training@thelia.org.uk For up-to-date information follow us on Twitter @sll100