Interview with... Jonathan Gittins

WN talks to the head of lighting at environmental design consultants Atelier Ten about creating an ecologically sensitive and sustainable lighting scheme for London's Illuminated River project

How has Atelier Ten been involved in Illuminated River?

Illuminated River is a public art installation transforming the River Thames in central London with an orchestrated series of light works than span nine bridges. The aim was to create an artwork through the city that could be enjoyed by everybody and to encourage people to use the river at night by making it more welcoming. Atelier Ten was appointed as technical lighting designer with the vision to install illuminations that are sensitive to the environment, both to the visual surroundings and to the ecology of the river and its inhabitants. 

What was your priority on starting the project?

When we started, we didn’t really have any information about the existing conditions of the bridges in their settings so we needed to get a reference point. We did two things: a luminance survey and a spill light survey. These were done to establish the lit environments around the bridges, which would then be used to inform how brightly we could set the new lighting. 

Most of the light fittings were very old, and on Westminster Bridge they were literally falling apart. We don’t know how long some of them had been there but they were all outdated, inefficient light sources covered in a lot of pigeon poo.

We were doing the surveys at the same time that Leo Villareal was developing the artwork, which meant it was a very joined-up design process without any big surprises for him to work around part way through. We carried out tests using mock-ups of the bridges and were able to tell him what light levels he should be going for from the outset. 

What did the luminance survey involve?

For this we walked 9 miles of the river from Tower Bridge to Albert Bridge and back photographing every inch of the riverbank with a special camera. We then converted these images into heat-map-style pictures showing the brightness of lighting on the bridges and the surrounding buildings. That allowed us to calculate the specific light settings for the new schemes. We didn’t want to over-light the structures or overpower the neighbouring landmarks, of which there are a lot along this stretch of the river. 

One of the surprising things the survey revealed was how brightly lit some of the existing riverside buildings are. Some are high above the recommendations you would find in any regulations or guidance. We were also astonished at how dark some areas of the river are, particularly past Westminster, and this meant we could light the bridges on the west end to a much lower level than we had expected. Conversely, on the bridges further east we had to ensure the new designs fitted in with the brighter surroundings. 

We’re hoping the information from the survey can also be used to encourage the owners of some of these very bright buildings to actually bring down their levels. That’s a wider piece of work off the back of this project. 

What about the light spill survey?

We went on a boat along the same route and measured how much light the old schemes were putting into the river. There were some bridges where light in the water was almost up to the levels used on motorways – really very high. We hadn’t expected that but it became one of the driving forces behind designing features on the new light fittings to help direct the illumination. 

We also found that some of the street lamps on the bridges were throwing a lot of light onto the river, rather than the road or paths. We’ve been talking to the local authorities that own the bridges and some of them have started installing measures to focus the light where it’s meant to be. 

What are the negative impacts of artificial light on the waterways?

There are a number of things. We had an ecologist on board from the early days who advised us on the impact to wildlife. A big worry was how the light could potentially affect the breeding cycles of fish. One element of Leo’s designs involved illuminating the faces of the bridges and if this was done incorrectly it could cause a strip of light across the water. The concern is that this might create a barrier across the river and the fish wouldn’t want to swim through it to spawn. There was a lot of work involved to avoid doing that, particularly close to the riverbanks and on the foreshore, where many of the breeding fish congregate. 

There’s been lots of research on how the colour of the light can affect different species too. Anything on the blue end of the spectrum can be more harmful to bats, so Leo’s palette uses really soft, muted colours and none of the really harsh blue shades. We know that there aren’t any bats using the bridges to roost but they may use the Thames as a path for feeding. 

We also had to consider people using the river, either walking along the bank or in boats, as there is the potential for glare. We designed special baffles on our fittings that would focus the light onto the face of the bridge, rather than onto the water, and tucked the fixtures into the structures so that it prevented any direct view of the lamps. 

How were the lights installed?

Everything had to be done by abseilers. It was the only way to get to the locations on the bridges without scaffolding out the whole structure, which would then start interfering with the waterway – keeping the river open throughout was essential. It meant quite a lot of overnight work when arches were able to be closed for limited periods. 

We worked out recently that we spent 80 nights of aiming the fittings and the baffles on the bridges after they had been installed by the contractor FM Conway. We had abseilers hanging off the bridges and us on a boat with a radio telling them to tilt up or down. It was really quite an involved process to make sure that we had light exactly where we wanted it.

Did you have to work around the heritage of the bridges?

Yes, we worked with the architects Lifschutz Davidson Sandilands and structural engineers Price & Myers to develop bespoke brackets because the bridges are very important listed structures. We weren’t allowed to permanently fix anything to many of them, so a lot of the lighting has been clamped in place to avoid doing any damage. There’s obviously a whole load of infrastructure – cabling etc – that we had to develop routes for as well. 

Illuminated River had to make over 30 planning submissions and 12 listed building submissions to get approval for doing all the work. It was a massive undertaking as not only do the bridges have different owners but they all fall within different local councils. And we had other considerations on the river too, such as the Port of London Authority. It was a very long design process to make sure we met every requirement that was demanded.

Have you carried out surveys on the new lighting schemes?

We have completed surveys on phase one (London, Cannon Street, Southwark and Millennium bridges) and found that the light levels were slightly lower than what we had set our targets to. It all worked out better than we thought, which is great. We’re going back on a boat to measure phase two (Blackfriars Road, Waterloo, Golden Jubilee, Westminster and Lambeth bridges), and are hoping for similar results. 

Is interest in more environmentally conscious lighting schemes growing? 

People are becoming increasingly aware of what external lighting can do, both good and bad. There’s more understanding that over-lit buildings are detrimental not just because of the energy they use but of how they impact the environment. The kind of work we’ve been doing for Illuminated River is a way of quantifying it – it is useful to put numbers to the brightness. It’s definitely an area that we’re seeing more interest in. 

What should be considered before installing new lighting on and around inland waterways? 

I would say two things. First there’s the setting – what the environment is like around the structure and the waterway. This is key to informing what it is you’re lighting and how bright it should be. Second are the fixings – working out the best way to mount and conceal the lighting, and then controlling the light so that it’s directed onto the structure rather than spilled and wasted. If you’re lighting only what’s needed, you’re saving energy and stopping it from going into the water – it makes sense on every front.

Find out more

Atelier Ten

atelierten.com

Illuminated River

illuminatedriver.london