Lighting is a critical component in a museum environment because, together with temperature, relative humidity and pollutants, it is one of the damaging factors able to produce long‐term, cumulative and irreversible photodegradation processes. To correctly preserve artworks, limiting illuminance and exposure is recommended, allowing on one side the preservation of the object, but on the other limiting

The development of the lighting profession toward the third stage requires our attention shifting from the light on certain planes to the light distributions in 3D spaces. In this article, we propose a practical strategy to measure the local density of illumination in 3D scenes based on the zeroth-order of spherical harmonics decompositions of a high dynamic range (HDR) panoramic map. The basic functional

Correlated color temperature (CCT) is a one-dimensional metric that aims to quantify the perceived visual quality of nominal white light sources. It is often used as a proxy for the color quality of light sources due to its ease of use. However, CCT lacks the accuracy in communicating color information for research purposes. Two light sources with identical CCTs can appear perceptually different, and

Correlated color temperature (CCT) is a one-dimensional metric that aims to quantify the perceived visual quality of nominal white light sources. It is often used as a proxy for the color quality of light sources due to its ease of use. However, CCT lacks the accuracy in communicating color information for research purposes. Two light sources with identical CCTs can appear perceptually different, and

Electric light in buildings may provide some health benefits; however, for most people these benefits are likely to be small. It is possible for electric lighting to cause health problems, if there is too little light or there is glare, but for the most part there is good guidance available and these problems can be avoided. The quality of the lit environment can have a psychological impact and this

Integrative lighting concepts, the process of including the physiological and psychological impacts from lighting into the design process for buildings and urban spaces, are still in their infancy. There are many aspects that are not known or only partially understood and this restricts the widespread application of integrative lighting. This paper explores some of the issues from the viewpoint of

Lighting for workplaces and schools is typically specified to meet the needs of the visual system without sufficient regard to the lighting characteristics that are required by the human circadian system. In 2020, many workers and students were compelled by the COVID-19 pandemic to work and study from home, where light levels are typically even lower than those found in most schools and workplaces

Alzheimer’s disease and related dementias is the collective term for a progressive neurodegenerative disease for which there is presently no cure. This paper focuses on two symptoms of the disease, sleep disturbances and depression, and discusses how light can be used as a non-pharmacological intervention to mitigate their negative effects. Bright days and dark nights are needed for health and well-being

Electric lighting has decreased dependence on natural light to illuminate the workplace. Humans are genetically predisposed to be day-oriented (diurnal) and depend on daylight to regulate circadian rhythms. Shift work will force workers to sleep and work at non-biological times, inducing circadian disruption with implications for workers’ safety and health. The scientific literature may be used in

Light at dawn and dusk is the key signal for the entrainment of the circadian clock. Light at dusk delays the clock. Light at dawn advances the clock. The threshold for human entrainment requires relatively bright light for a long duration, but the precise irradiance/duration relationships for photoentrainment have yet to be fully defined. Photoentrainment is achieved by a network of photosensitive

Typical home lighting practice is mainly centred on visual aspects to enable safe movement between spaces, flexibility in multiuse spaces, a sense of aesthetics and energy efficiency. Whilst lighting impacts on the health of residents have not received similar consideration, this area is gaining increasing interest. This is even more important and actual in the context of the recent pandemic where

This paper makes the case that a significant factor in the failure to ensure adequate daylighting performance for interior spaces is often due to the inadequacy of methods used at the early stages of planning. All of the methods currently used for daylight/sunlight planning share common failings: they cannot make meaningful estimations of performance at the outset, nor can the methods used be extended/refined

As lighting designers, our work impacts people and the environment. Putting human-centric thinking and approaches at the heart of design is the first principle. This paper reflects a personal view on what lighting designers need to know before they can apply professional judgement and claim that their lighting design will improve human health.

Photophobia (fear of light) occurs in a wide range of ophthalmic, neurological and behavioural conditions, the most common of which is migraine. The visual discomfort associated with migraine can occur not only in response to bright light but also flicker, spatial pattern and colour. The principles that underlie the discomfort are explored and methods to reduce it are proposed.

Electric light in buildings may provide some health benefits; however, for most people these benefits are likely to be small. It is possible for electric lighting to cause health problems, if there is too little light or there is glare, but for the most part there is good guidance available and these problems can be avoided. The quality of the lit environment can have a psychological impact and this

Integrative lighting concepts, the process of including the physiological and psychological impacts from lighting into the design process for buildings and urban spaces, are still in their infancy. There are many aspects that are not known or only partially understood and this restricts the widespread application of integrative lighting. This paper explores some of the issues from the viewpoint of

Lighting for workplaces and schools is typically specified to meet the needs of the visual system without sufficient regard to the lighting characteristics that are required by the human circadian system. In 2020, many workers and students were compelled by the COVID-19 pandemic to work and study from home, where light levels are typically even lower than those found in most schools and workplaces

Alzheimer’s disease and related dementias is the collective term for a progressive neurodegenerative disease for which there is presently no cure. This paper focuses on two symptoms of the disease, sleep disturbances and depression, and discusses how light can be used as a non-pharmacological intervention to mitigate their negative effects. Bright days and dark nights are needed for health and well-being

Electric lighting has decreased dependence on natural light to illuminate the workplace. Humans are genetically predisposed to be day-oriented (diurnal) and depend on daylight to regulate circadian rhythms. Shift work will force workers to sleep and work at non-biological times, inducing circadian disruption with implications for workers’ safety and health. The scientific literature may be used in

Light at dawn and dusk is the key signal for the entrainment of the circadian clock. Light at dusk delays the clock. Light at dawn advances the clock. The threshold for human entrainment requires relatively bright light for a long duration, but the precise irradiance/duration relationships for photoentrainment have yet to be fully defined. Photoentrainment is achieved by a network of photosensitive

Typical home lighting practice is mainly centred on visual aspects to enable safe movement between spaces, flexibility in multiuse spaces, a sense of aesthetics and energy efficiency. Whilst lighting impacts on the health of residents have not received similar consideration, this area is gaining increasing interest. This is even more important and actual in the context of the recent pandemic where

This paper makes the case that a significant factor in the failure to ensure adequate daylighting performance for interior spaces is often due to the inadequacy of methods used at the early stages of planning. All of the methods currently used for daylight/sunlight planning share common failings: they cannot make meaningful estimations of performance at the outset, nor can the methods used be extended/refined

As lighting designers, our work impacts people and the environment. Putting human-centric thinking and approaches at the heart of design is the first principle. This paper reflects a personal view on what lighting designers need to know before they can apply professional judgement and claim that their lighting design will improve human health.

Photophobia (fear of light) occurs in a wide range of ophthalmic, neurological and behavioural conditions, the most common of which is migraine. The visual discomfort associated with migraine can occur not only in response to bright light but also flicker, spatial pattern and colour. The principles that underlie the discomfort are explored and methods to reduce it are proposed.

The spectral responsivity of a photometer is usually measured using very narrow optical excitations, provided by a monochromator or a tuneable laser. This article describes a technique to measure the spectral responsivity using an arbitrary number of optical excitations having any type of spectral distribution. The problem is formulated as an inverse problem which is solved using a probabilistic approach

The Brazilian economic scenario promotes sustainable development by, among other actions, reducing the pressure on the expansion of electricity capacity. Furthermore, efficiency and reliability may be achieved through regulations and standardised production. From this perspective, there is a steadfast need for continuous improvement in the process of certification of products in the country. This shall

The spectral responsivity of a photometer is usually measured using very narrow optical excitations, provided by a monochromator or a tuneable laser. This article describes a technique to measure the spectral responsivity using an arbitrary number of optical excitations having any type of spectral distribution. The problem is formulated as an inverse problem which is solved using a probabilistic approach

The Brazilian economic scenario promotes sustainable development by, among other actions, reducing the pressure on the expansion of electricity capacity. Furthermore, efficiency and reliability may be achieved through regulations and standardised production. From this perspective, there is a steadfast need for continuous improvement in the process of certification of products in the country. This shall

In 2020, an LRT symposium on the topic of light and health was held over five 90 minute sessions, on successive days, in November. The objectives were to summarize the current state of knowledge in this field and to consider the implications for lighting practice. The result was a collection of presentations ranging from scientific reviews of the literature relevant to specific outcomes and applications

In 2020, an LRT symposium on the topic of light and health was held over five 90 minute sessions, on successive days, in November. The objectives were to summarize the current state of knowledge in this field and to consider the implications for lighting practice. The result was a collection of presentations ranging from scientific reviews of the literature relevant to specific outcomes and applications

Askola J, Kärhä P, Baumgartner H, Porrasmaa S, Ikonen E. Effect of adaptive control on the LED street luminaire lifetime and on the lifecycle costs of a lighting installation. Lighting Research and Technology 2021. Epub ahead of print 3 May 2021. DOI: 10.1177/4771535211008179

Askola J, Kärhä P, Baumgartner H, Porrasmaa S, Ikonen E. Effect of adaptive control on the LED street luminaire lifetime and on the lifecycle costs of a lighting installation. Lighting Research and Technology 2021. Epub ahead of print 3 May 2021. DOI: 10.1177/4771535211008179

Features of lighting that can influence people’s behaviours have been identified in an earlier study, along with six scenarios where these could be applied to solve problems with movements through railway stations. The current paper describes the development and testing of novel lighting interventions for three of these scenarios, with two new products controlled by the Internet of Things technology

Features of lighting that can influence people’s behaviours have been identified in an earlier study, along with six scenarios where these could be applied to solve problems with movements through railway stations. The current paper describes the development and testing of novel lighting interventions for three of these scenarios, with two new products controlled by the Internet of Things technology

This article explores the best practices for conducting psychophysical experiments that investigate how colour rendition influences the perception of architectural environments. We offer guidance that covers all stages of research from preliminary development to publication, focusing especially on experiments that investigate qualities such as perceived naturalness, vividness, preference or acceptability

This article explores the best practices for conducting psychophysical experiments that investigate how colour rendition influences the perception of architectural environments. We offer guidance that covers all stages of research from preliminary development to publication, focusing especially on experiments that investigate qualities such as perceived naturalness, vividness, preference or acceptability

Lighting Research & Technology depends on its reviewers to maintain the high standard of the journal. More generally, much of the authority that the scientific method rightly commands rests on the principle of peer review. Whilst reproducibility of results is generally accepted as a necessary feature of the scientific method, it is evidently the case that the findings from a great many published studies

A range of devices exist that follow the minutiae of our everyday lives. Our heart rates, steps and calories burned can all be logged, whether sleeping, running, cycling, sat at work or simply taking it easy. Once logged, these can be transferred digitally and analysed in a myriad of helpful, or sometimes quite bizarre, charts. Dosimeters or light-logging wearables in the form of electronic watches

Lighting Research & Technology depends on its reviewers to maintain the high standard of the journal. More generally, much of the authority that the scientific method rightly commands rests on the principle of peer review. Whilst reproducibility of results is generally accepted as a necessary feature of the scientific method, it is evidently the case that the findings from a great many published studies

A range of devices exist that follow the minutiae of our everyday lives. Our heart rates, steps and calories burned can all be logged, whether sleeping, running, cycling, sat at work or simply taking it easy. Once logged, these can be transferred digitally and analysed in a myriad of helpful, or sometimes quite bizarre, charts. Dosimeters or light-logging wearables in the form of electronic watches

Using experimental data from four electric lighting scenarios at King’s College Chapel in Cambridge, we developed an integrated approach to evaluating the overall impression of concert lighting. First, we performed a group analysis based on the aggregated response from the audience, conductor and musician respondents, followed by an overall analysis accounting for all 624 responses. Ordered logistic

Using experimental data from four electric lighting scenarios at King’s College Chapel in Cambridge, we developed an integrated approach to evaluating the overall impression of concert lighting. First, we performed a group analysis based on the aggregated response from the audience, conductor and musician respondents, followed by an overall analysis accounting for all 624 responses. Ordered logistic

There is insufficient current knowledge on the sky luminance patterns under ISO/CIE standard sky types in absolute luminance physical units in cd.m−2 and the resulting horizontal skylight illuminance in lux at the ground level. This paper explains research results and formulae to enable determination of computer applications which help in any location and time to calculate the distribution of luminance

There is insufficient current knowledge on the sky luminance patterns under ISO/CIE standard sky types in absolute luminance physical units in cd.m−2 and the resulting horizontal skylight illuminance in lux at the ground level. This paper explains research results and formulae to enable determination of computer applications which help in any location and time to calculate the distribution of luminance

The five articles in the current issue illustrate the broad range of topics associated with outdoor lighting – sky glow, road surface reflectance, road safety and visual performance. They describe the findings of new research so that other researchers can learn of the advance, can criticise, and can plan new hypotheses: gradually, the knowledge base improves.

Functional artificial lighting, when we get it right, is, mostly, unseen and innocuous. With a huge range of products now available at affordable prices, there has never been so much choice. But there is also a worrying lack of guidance regarding how much light is needed and how these products should best be installed. Indeed, there seems to be a belief that ‘brighter is better’ resulting in domestic

The five articles in the current issue illustrate the broad range of topics associated with outdoor lighting – sky glow, road surface reflectance, road safety and visual performance. They describe the findings of new research so that other researchers can learn of the advance, can criticise, and can plan new hypotheses: gradually, the knowledge base improves.

Functional artificial lighting, when we get it right, is, mostly, unseen and innocuous. With a huge range of products now available at affordable prices, there has never been so much choice. But there is also a worrying lack of guidance regarding how much light is needed and how these products should best be installed. Indeed, there seems to be a belief that ‘brighter is better’ resulting in domestic

We report for the first time the effect of ageing due to adaptive control of lighting on the lifecycle costs of luminaire installations. Two types of LED street luminaire were aged (1) as the luminaire lit for 9 hours and then switched off for 3 hours and (2) under intensive ageing using adaptive control conditions mimicking presence of vehicles, where the luminaires were switched with 30-second interval

We report for the first time the effect of ageing due to adaptive control of lighting on the lifecycle costs of luminaire installations. Two types of LED street luminaire were aged (1) as the luminaire lit for 9 hours and then switched off for 3 hours and (2) under intensive ageing using adaptive control conditions mimicking presence of vehicles, where the luminaires were switched with 30-second interval

Light can impact human health via the visual and non-visual systems originating in the retina of the eye or as optical radiation falling on eye or skin. This paper provides a summary of what is known about these impacts. Topics covered include aspects of lighting likely to cause eyestrain and headaches; increase the risk of falls; induce circadian disruption; enhance sleep; mitigate Alzheimer’s disease

Light can impact human health via the visual and non-visual systems originating in the retina of the eye or as optical radiation falling on eye or skin. This paper provides a summary of what is known about these impacts. Topics covered include aspects of lighting likely to cause eyestrain and headaches; increase the risk of falls; induce circadian disruption; enhance sleep; mitigate Alzheimer’s disease

The current pandemic has led us to ask many questions about our society and way of life and the design of the urban landscape. Societal norms that drive urban design are based upon the assumption that people are (relatively) healthy. Covid-19 shows this assumption is false, but buildings and urban spaces do not easily allow the adoption of new behavioural norms such as social distancing. Communal spaces

The importance of daylight in homes is widely understood. The ability of good daylighting to reduce reliance on electric lighting is only the beginning. People equate well daylit spaces with quality and enjoy the variation of natural light and direct sunlight that daylight brings. The key role of light exposure for health is also a major driver for good daylighting, as it is ideal for circadian entrainment

The current pandemic has led us to ask many questions about our society and way of life and the design of the urban landscape. Societal norms that drive urban design are based upon the assumption that people are (relatively) healthy. Covid-19 shows this assumption is false, but buildings and urban spaces do not easily allow the adoption of new behavioural norms such as social distancing. Communal spaces

The importance of daylight in homes is widely understood. The ability of good daylighting to reduce reliance on electric lighting is only the beginning. People equate well daylit spaces with quality and enjoy the variation of natural light and direct sunlight that daylight brings. The key role of light exposure for health is also a major driver for good daylighting, as it is ideal for circadian entrainment

Obstacle detection and facial emotion recognition are two critical visual tasks for pedestrians. In previous studies, the effect of changes in lighting was tested for these as individual tasks, where the task to be performed next in a sequence was known. In natural situations, a pedestrian is required to attend to multiple tasks, perhaps simultaneously, or at least does not know which of several possible

Obstacle detection and facial emotion recognition are two critical visual tasks for pedestrians. In previous studies, the effect of changes in lighting was tested for these as individual tasks, where the task to be performed next in a sequence was known. In natural situations, a pedestrian is required to attend to multiple tasks, perhaps simultaneously, or at least does not know which of several possible

Many applications in various fields require uniform illumination from light sources, for example, in medical imaging in the biophotonics area. In this work, the design and application of an annular light-emitting diode array capable of producing a homogeneous irradiance pattern is presented. As part of the design process, software that allows the simulation of the irradiance pattern as a function of

This study examined the effects of lighting colour on emotional states and the effects of ethnicity on the impact of lighting colours on emotional states, based on the Mehrabian and Russell’s emotional state model measuring pleasure, arousal and dominance. It was hypothesised that there are significant differences in pleasure and arousal among six lighting colours: red, green, blue, yellow, orange