Lighting the City: Public Space After Dark

Urban lighting has become increasingly measurable, controllable, and efficient. Yet despite advances in metrics, sensing technologies, and adaptive systems, many contemporary nightscapes remain fragmented, perceptually incoherent, and ecologically misaligned. This discrepancy points to a fundamental limitation: while light is extensively measured, it is insufficiently understood as a relational condition.

This paper argues that the central challenge of contemporary lighting is no longer illumination, but calibration.

Current lighting practices are largely grounded in quantitative paradigms – illuminance levels, uniformity ratios, glare indices, and energy performance. While essential for safety and standardization, these metrics often operate in isolation from the lived, spatial, and biological realities of the urban night. As a result, environments that are technically compliant may fail to support legibility, social presence, or ecological balance. Light is optimized, yet misaligned.

Positioning light as both a sensed and sensing medium, this research aligns with emerging interdisciplinary approaches that bridge measurable and experiential dimensions. It proposes a shift from illumination as provision toward calibration as relational alignment – where light is continuously tuned in relation to spatial morphology, human perception, temporal rhythms, and multispecies ecologies. Rather than maximizing brightness, calibration seeks to organize relations: between exposure and protection, continuity and contrast, visibility and darkness.

To operationalize this shift, the paper introduces the LIGHTMAP framework – a multidimensional calibration matrix integrating eight interdependent domains: Life, Identity, Governance, History, Technology, Morphology, Atmosphere, and Pattern. LIGHTMAP functions simultaneously as a conceptual model, analytical tool, and design instrument, enabling the identification of systemic misalignments and guiding context-sensitive intervention across scales.

The framework is applied through a case study of Florentin, a dense mixed-use neighborhood in Tel Aviv characterized by morphological complexity, social diversity, and layered luminous conditions. The analysis reveals a consistent pattern of miscalibration: technologically precise yet spatially insensitive illumination, uniform lighting strategies applied to heterogeneous environments, and energy-efficient retrofits that overlook perceptual and ecological thresholds. These conditions do not produce darkness, but incoherence – flattening spatial hierarchy, weakening legibility, and intensifying both perceptual and environmental vulnerability.

Methodologically, the study combines multimodal urban analysis, including spatial mapping, on-site observation, photographic documentation, and perceptual assessment, structured through the LIGHTMAP matrix. Each dimension operates as a diagnostic lens, enabling the identification of specific forms of misalignment – such as discrepancies between luminous intensity and spatial hierarchy, or between spectral composition and ecological sensitivity. This approach supports a shift from descriptive analysis toward actionable calibration, where lighting is evaluated not only by measurable performance, but by its capacity to sustain coherent and context-responsive urban conditions.

Through the LIGHTMAP framework, the study demonstrates how calibrated interventions can reorganize luminous relations -transforming fragmentation into continuity, intensity into hierarchy, and exposure into balanced legibility. Importantly, calibration does not imply increasing or reducing light levels, but reconfiguring their distribution, spectrum, and interaction with context.

The contribution of this research is threefold. Conceptually, it reframes urban lighting as a relational and multi-systemic field rather than a technical subsystem. Methodologically, it introduces LIGHTMAP as an integrative framework for diagnosing and designing urban night environments. Practically, it offers a transferable approach for aligning lighting systems with urban complexity in ways that support human experience, ecological sensitivity, and spatial coherence.

Within the framework of Sensing Light, this paper suggests that light must be understood not only as something we measure or perceive, but as a condition that requires continuous calibration. Restoring measure, in this sense, is not a return to uniformity, but a reorganization of relations—where light becomes an instrument of alignment, care, and urban responsibility.

A central aspect of lighting research is the effective communication of findings, enabling reflective dialogue with professional practice and facilitating implementation to benefit society. While a growing body of evidence demonstrates the importance of lighting for socially sustainable urban public spaces after dark, the translation of this knowledge into practice remains a key challenge. Practitioners require accessible, evidence-based guidance and support for research-informed design decisions to create inclusive, safe, and socially vibrant public spaces after dark. This need aligns with the United Nations Sustainable Development Goal 11.7, which calls for universal access to safe, inclusive, and accessible public spaces.

This project addresses this challenge by translating research findings into an accessible visual format, using film as a medium to support knowledge exchange between researchers, designers, students, and policy-makers. Visual media have been shown to play an important role in shaping understanding and supporting the application of scientific knowledge beyond academic contexts, particularly when combined with interactive discussions (Nutley et al., 2007). By communicating research insights in a pedagogical and engaging format, the project promotes the implementation of research-informed lighting design in practice. As an educational film, the project expands the modes of dissemination within lighting research, enabling broader accessibility and engagement across disciplines and professional domains, as well as among students and the general public. The film thereby functions as a tool for education, policy development, and practice, supporting a more integrated approach to lighting design that acknowledges the complex relationship between light, perception, and human behaviour.

The narrative of the film is largely based on the doctoral thesis Sustaining Social Interaction in Public Squares After Dark: A Socio-Physical Perspective on the Lighting–Behaviour Relationship (Hennig, 2025). Through interviews with two contributors from research and practice, the film discusses key findings from the thesis and their implications for practice, alongside an in-depth dialogue regarding the theory – the socio-physical perspective on the lighting-behaviour relationship in public space. The thesis employs a transactional-contextual framework, focusing on the dynamic interplay between individuals and their everyday environmental settings. To address the role of lighting in sustaining social interaction after dark, it draws on Daniel Stokols’ conceptualization of modes of human–environment transactions (Stokols, 1978).

The film is structured in three parts of approximately 8-10 minutes each. The first part defines public spaces as socio-physical environments, outlining how they support mobility, stationary activities, and social interaction, and how access to inclusive public spaces after dark contributes to quality of life and well-being. The second part presents the theoretical framework, introducing a socio-physical conceptual model of human–environment transactions. Central to this model is environmental appraisal, including perceived atmosphere, visual accessibility, reassurance, and restorativeness. Lighting conditions shape these appraisals and, consequently, influence behaviour and patterns of social interaction. The third part focuses on practical application, presenting findings from an intervention study and translating these into lighting principles. Through dialogue with practice, the film illustrates how theoretical insights can inform lighting strategies that support diverse user needs and promote social interaction, highlighting the potential of lighting design to contribute to socially sustainable urban development when grounded in empirical research.

The film features contributions from Daniel Stokols, Chancellor’s Professor Emeritus at the University of California, US, and Kristin Bredal, founder and creative director of Zenisk, Norway.

Production timeplan: April–June 2026.

Proposed set-up: Premiere at Light Symposium 2026, followed by a Q&A session with the author.

Funding: Bertil och Britt Svenssons stiftelse för belysningsteknik.

Manuscript: Vivi Katarina Ruberg Hennig.

Film producer: Rex Brådhe, Illustrafilm.

Acknowledgment to my supervisors: Maria Johansson, Steve Fotios, Niko Gentile, Catharina Sternudd, Pimkamol Mattson, and to Åsa Gullstrand and Johan Moritz at Malmö Stad for their collaboration.

INTRODUCTION

The route selection process in complex urban environments is often influenced by environmental stimuli processed at a subconscious level. In urban centers, particularly those characterized by steep topographical variations, the perception of “discomfort” related to slope acts as a physical deterrent, limiting the equitable distribution of pedestrian flows. By applying light signals calibrated for geometry, height, and CCT, this study aims to influence route choice, guiding pedestrians toward identity-rich pathways that, despite being perceived as strenuous, are strategic for urban valorization. While pioneering studies analyzed route selection in indoor “T” or “F” junctions, highlighting how brightness and width act as “affordances,” this study focuses on the “Y” intersection, a geometry frequently found in complex, organic urban fabrics adapted to the terrain. The “Y” junction is a pure Point of Decision (POD): it ensures simultaneous choice, neutralizing “Visual Momentum” and making the light signal the primary sensory input capable of guiding user preference.

METHODS

The methodology adopts a visual affordance evaluation protocol using Virtual Reality (VR). The urban Y-junction, featuring two perfectly symmetrical branches, is explored via a VR headset using 360° stereoscopic imagery to ensure digital immersion. The pilot test is based on the guided choice method, placing the subject at a fixed start point facing the intersection. Scenarios present a conflict between a flat path and one with a critical slope, utilizing neutral textures to isolate the lighting variable. The innovation lies in applying “Long Range” (LR) and “Short Range” (SR) light signals, terms recalling historical communication systems for long and short-distance messaging:

Long Range (LR): A “Landmark” positioned at height (approx. 3 m) on the corner facade of the sloped branch. It features a warmer CCT, yet distinct from general lighting, and narrow optics (10-15°), creating a directional arrow via a wall-wash effect to serve as a visual vector for long-distance wayfinding.

Short Range (SR): A signal positioned at eye level on the same facade. It also features a CCT that differs from the general ambient lighting, maintaining the same geometry as the “LR” signal but with various orientation trials to guide the user in the immediate proximity of the junction.

Data is collected through a Likert-scale perceptual questionnaire focused on visual attractiveness, signal clarity, orientation effectiveness, and the perceived effort of the slope.

EXPECTED RESULTS AND CONCLUSIONS

The study expects to demonstrate that the LR signal, acting as a “beacon,” reduces early decisional uncertainty, while the SR signal serves as close-range confirmation. The goal is to identify a threshold where the lighting nudge neutralizes the negative bias of physical effort in the presence of a road slope, transforming an ‘uncomfortable’ route into a preferred choice. In conclusion, the study validates VR as a tool for defining non-invasive guidance protocols, demonstrating how photometric calibration can rebalance urban livability through perception-based design.

Placemaking does not end after dark. However, the experience of outdoor space at night remains one of the most consistently neglected aspects of public realm design. Housing estates, residential streets, communal courtyards, playgrounds: the everyday spaces where most people actually live their lives are rarely designed with after dark use in mind. They are not the projects that appear in award submissions. They are not the spaces setting the agenda.

What they do is tell a different story where lighting decisions are made almost entirely on the basis of technical compliance, where a standard streetlight is considered a sufficient answer and where the assumption that more light and more efficient lighting, equals better, and safer, approach goes almost entirely unchallenged. The lived experience of the people who actually use these spaces after dark and how the light makes them feel, whether it draws them in or drives them away, whether it is designed to support the way they actually gather, move and dwell in a place is rarely part of the conversation.

Drawing on selected case studies from the UK and Europe, this paper examines the development and testing of new methods for engaging directly with communities about their experience of outdoor lighting. It focuses on the role that temporary lighting trials, on-site demonstrations and discussions play in allowing residents and stakeholders to respond to different lighting approaches before permanent decisions are made.

Most notable is that on-site trials repeatedly expose a significant disconnect between technical assumptions and lived experience. Communities identify priorities that standardised approaches routinely overlook including the warmth and quality of light valued above only quantity; the illumination of social gathering points prioritised; over-lit environments reported as heightening, rather than reducing, feelings of safety and security. On site after dark engagement reveals further patterns of exclusion that are not visbile during the day or in laboratory conditions.

Utilising community centred after dark engagement as a legitimate source of primary research data creates a significant opportunity to create closer, more productive collaboration between design practice, academia, and industry that is grounded in evidence that actually reflects how people live and experience environments.

A number of cities and municipalities are already moving in this direction by exploring engagement-led approaches and in-situ demonstrations as core tools in how they plan and deliver outdoor lighting. The lighting profession now has a clear opportunity, and a responsibility, to follow that lead to develop methodologies that close the gap between technical best practice and lived experience, and in doing so, to begin addressing the very real inequalities that poor outdoor lighting creates after dark.

Light plays a crucial role in shaping the perception, legibility, and nighttime experience of urban public spaces. Within complex urban regeneration processes, however, lighting design must be addressed in relation to multiple spatial and environmental dimensions, requiring approaches that support coordination across design perspectives.

This paper is developed within an ongoing multidimensional, project-oriented research focused on the regeneration of the IRCCS University Hospital of Bologna – Sant’Orsola Polyclinic, a pavilion-based healthcare complex embedded within the urban fabric. The research approach involves multiple contributors working on the same spatial context from different disciplines, including urban design, architectural design, urban greenery, and environmental factors such as noise, microclimate, and air pollution. The aim is to define a masterplan to guide and support coordinated spatial and environmental interventions across the hospital area, addressing public space design, accessibility, environmental performance, and the overall identity and integration of the complex within the urban context, while ensuring an integrated vision.

By considering lighting as a key component of the urban quality to be pursued through the regeneration process, this paper investigates how lighting can be designed and integrated as a spatial and perceptual layer of the urban realm, by exploring the nighttime experience of public spaces.

To establish a lighting design approach that takes into account the complex relationships between lighting and the many needs to meet in the urban environment, the study adopts a transdisciplinary design framework based on a criteria-driven model for multidimensional design, “The Lighting Design Experiment Model” (Hansen e Mullins 2014), supporting the positioning and future integration of lighting within a multidimensional urban regeneration process. The model structures the design process through a sequence of five phases. Based on a shared vision, criteria referring to different academic fields are defined, translated and transformed into a design solution, that can be validated within each academic field and criteria. The articulation of discipline-specific criteria, and the iterative development and evaluation of design propositions ensures a transdisciplinary design process.

The model is applied to a pilot site at the main entrance of the Sant’Orsola complex, conceived as a critical gateway between the city and the hospital, where identity, recognisability, orientation, accessibility and spatial legibility become central for the actual and future configuration of the site. The process follows the different phases of the model, translating knowledge from multiple domains (natural science, social science and humanities/art), into a shared framework. Particular attention is given to how lighting contributes to visual attention, saliency and wayfinding, while remaining open to inputs from parallel disciplinary investigations.

The paper discusses an ongoing process in which the model is used to structure the development of a lighting design strategy, while identifying how and where additional needs and requirements – related to broader masterplan objectives – can be progressively incorporated over time. In this sense, the framework operates not only as a design method, but also as a tool to support coordination among different perspectives working within the same spatial context.

The paper argues that the transdisciplinary approach of the Lighting Design Experiment model provides added value in complex urban regeneration processes by incorporating knowledge from the arts and humanities, natural sciences, and social sciences. At the same time, it demonstrates how the model can adapt to a multidimensional design context, such as the Sant’Orsola project, where multiple spatial components continuously reshape initial conditions. In this sense, the paper suggests how inputs emerging from different spatial dimensions can be progressively integrated into the model, supporting an ongoing process of dialogue and adjustment within a shared design framework.

Introduction

An urban lighting project that was born as a dynamic, responsive experimental installation has resulted in a handbook of criteria and guidelines to implement a holistic perspective in lighting projects for urban parks in the metropolitan region of Barcelona (Spain). The story begins with an applied research project in public space, promoted by CICAT Lighting Cluster, where control technology is used to implement a framework that is grounded on scientific evidence: from the ecological perspective to health and well-being applied to urban design, and from feminist and social perspectives to environmental justice.

Case Study description

This presentation proposal wants to be a follow-up to the published paper Urban-Centric Lighting Task Group: Tactical Lighting as an innovation strategy (DOI 10.1088/1755-1315/1099/1/012043). In the 2022 edition of Light Symposium in Copenhagen, we presented a framework for applying innovation through tactical interventions in urban spaces, sharing the first results of the recently installed proof of concept in a public park (Parc del Molinet, in Santa Coloma de Gramenet).

The Metropolitan Government of Barcelona (AMB), responsible for managing the park, assessed the viability and scalability of the strategies that were tested and decided to apply the strategies to the whole site. The construction finished in December 2025.

Once the initial assessment was found successful, while the scalation of the project was ongoing, AMB commissioned CICAT (Catalonia Lighting Cluster) to organize and lead the evolution of the applied theoretical framework into a set of guidelines and principles to be used by their internal engineering department in future lighting projects for green parks.

Open Discussion

The initial values that motivated the research, were categorized to better understand the complexity of the dynamics and tensions that affect public space, to organize the context:

a) Methodological approach: How innovation in urban lighting can benefit from temporary, experimental projects in urban space?

b) Human health and equity: Is it possible to identify a set of tools appliable to urban lighting design that is objective and represents an evolution in terms of health and environmental justice for our cities’ habitants?

c) Ecosystemic approach: How can a set of guidelines guarantee the minimum biological interference with the non-human living organisms in an urban environment?

d) Connectivity: How much smart does a city lighting system need to be for such environmental and health purposes?

e) Darkness and access to nature: What will be the evolution in the intersectional spaces between urban and natural spaces?

The assessment of the proof of concept was an effective tool that helped to challenge the assumptions and preliminary applied strategies that derived from the theoretical framework.

The strategic guidelines are now organised as a handbook, around 6 guiding principles, and describe a set of 33 project requirements based in the application of the guiding principles to the identified project zones. The handbook will be used as a quality standard, for evaluation and design purposes.

We would like to share the most relevant innovations that are being proposed in the new guidelines for challenging them and discuss the opportunity and proportionality of the requirements with the community. Our intention is to dedicate half of the time of the session to an open discussion of this first working version of the document, the “Handbook for Evaluation and Design of Public Lighting in Metropolitan Parks”.

More than a hundred years ago, Stockholm -like many other European cities, was illuminated by gaslight. The painter Eugène Jansson, often called “the blue painter,” captured the city’s gaslight shimmering in darkness. A century later, the picture is a different one.

Looking back at the history of light sources -from fireplaces and candlelight to gas lighting, arc lamps, incandescent bulbs, fluorescent tubes, metal halide lamps, and LEDs – each successive development has produced increasingly greater amounts of light. Over the past fifteen years, LED technology has established itself as the standard light source in both professional and consumer markets, while earlier technologies have gradually been phased out. Its widespread adoption is largely due to a combination of higher energy efficiency, longer lifespan, control possibilities, and steadily decreasing costs.

According to Kyba & al, measurements from calibrated satellites show that between 2012 and 2016 the Earth’s artificially lit outdoor area increased by about 2.2% per year. One of the central aims of the ongoing “lighting revolution” is to reduce energy consumption. However, this goal may be undermined by a rebound effect, in which lower costs lead to increased use of light. When a resource becomes more efficient to use, total consumption of that resource can rise rather than fall. This phenomenon is known as the Jevons Paradox, named after the economist William Jevons, who observed in 1865 that improvements in coal-burning steam engines actually increased coal consumption in Britain, as coal became cheaper and industrial production expanded.

As a practitioner who began working in public environments at the time when LED had become the standard light source, I have witnessed the challenges of planning lighting at appropriate levels – often trying to lower the amount of light. In an effort to understand what is happening in practice, I initiated an empirical study analyzing lighting conditions in different sites and cities as a way to document the shift to LED. To do so, I first developed a simple methodology for case studies. A site is selected, photographed using HDR imaging, and illuminance levels are measured. Recording minimum and maximum values provides a rough indication of the overall amount of light and the degree of uniformity. Most case studies have been conducted in Sweden, but investigations have also been carried out in Copenhagen and Berlin.

Following a historical overview of the development of lighting technology in Stockholm, selected case studies from Stockholm, Copenhagen, and Berlin are presented and discussed. Preliminary results suggest that light levels in Stockholm and Copenhagen do not appear to be higher with LED than they previously were with metal halide lamps, which may be explained by improved control capabilities. However, capitals are at the forefront of lighting management. In smaller cities, where investments in control systems have yet to be implemented, the situation looks different.

Copenhagen, often described as a comparatively dark city at night, does not show significantly lower light levels than Stockholm. However, the number of light points is considerably lower, and façade lighting and illuminated signage are largely absent -although this appears to be changing. In the case of Berlin, where the aim was to observe remaining gas lighting, it was found that illumination levels on streets with gas fixture are comparable to those in historic city centres in Stockholm and Copenhagen, where historical lanterns have been retrofitted with LED technology. Another outcome of the study concerns how existing infrastructure influences lighting levels over time, particularly when older fixtures are gradually replaced.

The research has been made possible through support from the Glödlampsfabrikernas Scholarship Fund from KTH and the Bertil & Svensson Foundation.