Light, whether natural or artificial, is a powerful material. It is fundamental to our lives, and it can help create new and interesting spaces in many different ways.

Even though this tends to be unrecognised in most discussions, lighting is currently gaining a new momentum. It was given official status when the UN designated 2015 as the “UN Year of Light”. And, fuelled by new technologies, it has now taken centre stage in all sorts of discussions: on the economic and environmental costs of climate change, on aesthetics and city branding, and on the quality of life in cities.

Bright street lights left to shine on empty streets are an excessive and unnecessary waste of energy that is bad for the planet. Images taken from space show vividly how much light is generated in our cities, and there are many attendant problems: high carbon levels, and light pollution which can result in poor sleep for humans and changes in nocturnal animal behaviours, to name but a few.

But light plays a huge role in creating social spaces, too. It is the backdrop for all social interaction, influencing what we can do after dusk, how safe we feel, and how well we can navigate through nocturnal environments.

Before the introduction of street lighting, it was dangerous to be out on the city streets after sundown. To walk the city at night, you had to hire a servant or “link boy” to walk ahead of you, lighting the path ahead. In electrified places today, we are so used to artificial light at the flick of a switch that we barely register it, except when it fails us. We are most aware of our dependence on electricity and artificial light when there is a power cut.

Western societies, and increasingly those farther afield, now have reliable artificial light technologies. However, not all of us benefit equally from this new status of light and lighting: looking at the lighting in different kinds of urban spaces can actually tell us quite a bit about social inequalities.

In London, for example, social housing estates tend to be brightly and harshly illuminated to allow for better CCTV surveillance, which is assumed to prevent anti-social behaviour. This kind of lighting marks these space as “dangerous” or “problematic”, regardless of whether or not this is actually the case.

In fact, darkness has become some sort of luxury good in London. Neighbourhoods that are well-off are usually not only darker and free from these crude lighting interventions; they also have much softer nightscapes which feel calm and safe and are aesthetically pleasing.

In the context of ever-emerging new technologies and design expertise, it is hard to understand why lighting still heightens social inequalities rather than combatting it. This issue is a concern of the Configuring Light/Staging the Social (CL) research programme, an interdisciplinary research programme currently based at King’s College London and the LSE.

A core concern of the programme is to foster cross-disciplinary dialogue and impact-oriented academic-practitioner collaborations around lighting and social research. One aspect of our work is public education. This week, along with the lighting design firm Speirs+Major, CL is hosting a night talk and walk in London’s Pimlico area as part of the Inside Out festival.

Pimlico is an interesting neighbourhood: some streets were never electrified, and there are still 1,500 gas lamps. Taking a walk down these streets is like taking a step back in time. The quality of the light is so totally different to that we find on most city streets: warm, orange light bathes the pavement, and it is considerably darker than most streets you’d encounter in London or any other major city.

On the night walk, our designers take light readings from the gas lamps using a light meter, to show how low the “lux” level is. This experience of a dark street, illustrates how well our eyes can deal with low levels of illumination, largely because the light in is uniform. What is hard for our eyes to deal with is high contrast: walking from brightly lit streets, our eyes find it hard to adjust if adjacent streets are lit to relatively lower levels, even if those lower levels are perfectly fine.

We hope the event will help create a dialogue about how we might turn the lights down a bit. With new “smart” LED lighting providing unprecedented control over “responsive” and “intelligent” lighting, there’s potential to reduce our light consumption.

Joanne Entwhistle (King's College, London), Don Slater and Mona Sloane (London School of Economics) are running the Configuring Light project.

She is speaking at “Light Walk: Night Talk” as part of the Inside Out Festival, a two part event combining a talk on light as material with a group walk around nocturnal Pimlico, where there are still working gas lights. You can book your free place here.