Search Results (16)

The rapid expansion of metro systems has exacerbated lighting-related issues, including uneven illuminance, glare, and blind spots. These issues compromise passenger visual comfort and perceived safety. Previous research has predominantly focused on individual lighting parameters, paying little attention to the combined effects of multiple factors. Perceived safety is a core objective in metro space design and is particularly susceptible to adverse visual environments. This study uses field measurements, virtual environment simulations, and eye tracking experiments to investigate the influence of lighting conditions and interface design (ceiling height and material) on visual comfort and perceived safety. The findings indicate that light-coloured, low-reflectance materials enhance visual guidance, whereas dark, high-reflectance surfaces induce frequent gaze shifts and diminish perceived safety. The optimal environmental benchmark parameters were illuminance levels of 140–270 lux and a correlated color temperature (CCT) of 4428–6250 K. This study also discusses optimizing interface design parameters in different spatial contexts. It also revealed systematic correlations between lighting parameters and spatial geometry, particularly regarding ceiling height. Elevated spaces require increased illuminance and color temperature to compensate for light attenuation, while areas with low ceilings necessitate reduced lighting intensity and warmer color temperatures to mitigate oppressive sensations. This evidence provides a human-centered theoretical foundation for lighting design in underground transport spaces. Full article

Urban parks often represent the last viable habitats for wildlife in city centres, functioning as crucial refuges and biodiversity hotspots for a wide array of plant and animal species. This study investigates the issue of light pollution in urban parks in selected Polish cities from the perspective of sustainable urban development and dark-sky friendly ordinances. Field data conducted in 2024 and 2025 include measurements of Upward Light Output Ratio (ULOR), illuminance, luminance, correlated colour temperature (CCT), and spectral characteristics of light sources. In addition, an analysis of changes in the level of light pollution in the studied parks and their surroundings between 2012 and 2025 was performed using data from the VIIRS (Visible Infrared Imaging Radiometer Suite) located on the Suomi NPP satellite. Results highlight the mismatch between sustainable development objectives and the current practice of lighting in most of the analysed parks. The study emphasises the need for better integration of light pollution mitigation in urban spatial policies and provides recommendations for environmentally and socially responsible lighting design in urban parks. Full article

Primary school students, as the main users of classrooms, are directly affected by the lighting environment, which not only affects their visual comfort but also their cognitive performance. This study investigated the effects of different correlated colour temperature (CCT) levels in classroom lighting on the cognitive performance of primary school students based on a multidimensional evaluation combining physiological signals (EEG and EDA) and subjective assessment. In this study, 53 subjects aged 10–13 years old from a primary school in Anshan City were used in a controlled experiment under five CCT conditions (3000 K, 4000 K, 5000 K, 6000 K, and 7000 K) at a constant illumination level of 500 lx. EEG and skin conductance (SC) signals were collected and subjective perceptions of visual comfort and fatigue were assessed while cognitive tasks were carried out. The results showed that students performed best cognitively at a colour temperature of 4000 K, with the lowest EEG absolute power (AP) (p < 0.01) and highest comfort (p < 0.05). Females were more sensitive to colour temperature changes and showed better cognitive performance in cooler colour temperature conditions, while male students performed better in warmer light conditions (p < 0.01). The above findings suggest that optimising the CCT of classroom lighting enhances students’ cognitive functioning and comfort, providing empirical support for lighting design guidelines in educational environments. Full article

Numerous studies have explored the role of colour in classroom environments and its effects on learning, cognition and motivation. However, research on coloured lighting remains limited, with most studies focusing only on correlated colour temperature (CCT). Addressing this gap, our study examines various chromatic lighting conditions that enhance learning outcomes while allowing for dynamic applications in educational settings. Conducted over three academic years in six primary classrooms, this quasi-experimental study employed a pretest and a control group to assess the effects of three chromatic lighting scenarios (orange, green and purple) on cognitive processes, emotional responses and basic instrumental learning. Descriptive, variance and comparative analyses revealed conclusive evidence of coloured lighting’s impact, though effects varied across different variables. The study highlights the potential of dynamic lighting approaches to support learning and suggests that AI-assisted lighting adjustments could aid teachers. The findings support the broader implementation of coloured lighting in primary classrooms, advocating for cost-effective, sustainable and adaptive solutions beyond conventional lighting. Such advancements are expected to enhance students’ learning, cognition and motivation while providing greater flexibility in educational environments. Full article

Energy consumption in buildings is linked to lighting technology. Light-emitting diode (LED) technology includes lamps and luminaires for general lighting applications. Due to their structure, LED lamps are expected to generate specific waste electrical and electronic equipment (WEEE) streams. LEDs are the main source of luminous flux, and their elemental composition is of particular interest to the recycling sector. In this study, surface-mount device (SMD) LEDs from six types of LED lamps (E27, E14, G9, R7S, GU10, and MR16) were removed, collected, separated by correlated colour temperature (CCT) (2700 K, 3000 K, 4000 K, and 6500 K), and characterised for the presence of rare earth elements and precious metals. They were digested with HNO₃, aqua regia, and HF in a hot plate and characterised by inductively coupled plasma mass spectrometry (ICP-MS). The concentration of each element as a function of CCT ranged as follows: lanthanum, 242–1840 mg/kg; cerium, 132–284 mg/kg; europium, 15–69 mg/kg; gadolinium, 1.9–3.8 mg/kg; terbium, 0.1–0.4 mg/kg; lutetium, 29–6381 mg/kg; yttrium, 4804–11,551 mg/kg; silver, 2712–5262 mg/kg; gold, 502–956 mg/kg; and palladium, 32–110 mg/kg. These results indicate the need for selective removal and separate recycling processes of SMD LEDs from LED lamps. Full article

Studies have shown that illuminance and correlated colour temperature (CCT) are strongly correlated with body responses such as circadian rhythm, alertness, and mood. It is worth noting that these responses show a complex and variable coupling, which needs to be solved using accurate mathematical models for the regulation of indoor light parameters. Therefore, in this study, by weighing the evaluations of visual comfort, alertness, valence, and arousal of mood, a multi-objective optimisation mathematical model was developed with constraints conducive to the healthy rhythm. The problem was solved with the multi-objective evolutionary algorithm based on the decomposition differential evolution (MOEA/D-DE) algorithm. Taking educational space as the analysis goal, a dual-parameter setting strategy for illuminance and CCT covering four modes was proposed: focused learning, comfortable learning, soothing learning, and resting state, which could provide a scientific basis for the regulation of the lighting control system. The alertness during class time reached 3.01 compared to 2.34 during break time, showing a good light facilitation effect. The proposed mathematical model and analysis method also have the potential for application in the lighting design and control in other spaces to meet the era of intelligent, highly flexible, and sustainable buildings. Full article

The hygiene area is one of the most important facilities in a space station. If its environmental lighting is appropriately designed, it can significantly reduce the psychological pressure on astronauts. This study investigates the effect of correlated colour temperature (CCT) on heart rate, galvanic skin response, emotion and satisfaction in the hygiene area of a space station. Forty subjects participated in experiments in a hygiene area simulator with a controlled lighting environment. The lighting conditions included 2700 K, 3300 K, 3600 K, 5000 K and 6300 K; physiological responses (heart rate, galvanic skin response), as well as emotion and satisfaction, were recorded. The results showed that CCT significantly influenced the participants’ physiological and subjective responses in the space station hygiene area. 6300 K led to the best emotion and satisfaction levels, the highest galvanic skin response and the lowest heart rate. The opposite was true for 2700 K. Full article

Outdoor urban lighting design is a complex issue. It involves multiple aspects (energy consumption, lighting pollution, aesthetics, and safety) that must be balanced to make sustainable decisions. Although the energy and environmental issues assumed a driving role in the optimization of the urban lighting design, its impact on the psychophysical well-being of individuals has received less attention. Artificial lighting has been shown to add several meanings to an individual’s experience of space: affective (affect, emotion, mood), cognitive (attention, imagination, perception), associative (memory, judgment), and motivational (closeness, openness, communication). Traditionally, studies on the effects of lighting on individuals’ emotions have mainly focused on indoor spaces, while the present study aims to investigate the influence of lighting on individuals’ emotions in an outdoor environment. Participants experienced a simulated urban park through virtual reality. Specifically, the urban park was shown with different combinations of overall illuminance (high vs medium vs low) and correlated colour temperature (CCT) (warm vs intermediate vs cool). For each combination, participants were asked to judge how they felt. In general, results showed that high-intensity cool light made participants more nervous, while warm light made individuals feel more tired and less motivated to explore the park. In contrast, an intermediate CCT at low or medium illuminance impacted individuals positively. Finally, it was found that participants’ mood predicted the impact that park lighting would have on them. These results suggest that assessing the influence of lighting on individuals’ emotions allows the decision-makers to implement the type of artificial lighting that will simultaneously safeguard both the well-being of individuals and the environment. Full article

One of the most important elements during photogrammetric studies is the appropriate lighting of the object or area under investigation. Nevertheless, the concept of “adequate lighting” is relative. Therefore, we have attempted, based on experimental proof of concept (technology readiness level—TRL3), to verify the impact of various types of lighting emitted by LED light sources for scene illumination and their direct influence on the quality of the photogrammetric study of a 3D urban mock-up. An important issue in this study was the measurement and evaluation of the artificial light sources used, based on illuminance (E), correlated colour temperature (CCT), colour rendering index (CRI) and Spectral power distribution (SPD) and the evaluation of the obtained point clouds (seven photogrammetric products of the same object, developed for seven different lighting conditions). The general values of the quality of the photogrammetric studies were compared. Additionally, we determined seventeen features concerning the group of tie-points in the vicinity of each F-point and the type of study. The acquired traits were related to the number of tie-points in the vicinity, their luminosities and spectral characteristics for each of the colours (red, green, blue). The dependencies between the identified features and the obtained XYZ total error were verified, and the possibility of detecting F-points depending on their luminosity was also analysed. The obtained results can be important in the process of developing a photogrammetric method of urban lighting monitoring or in selecting additional lighting for objects that are the subject of a short-range photogrammetric study. Full article

Lighting plays a fundamental role in learning spaces as it influences students’ performance. Nowadays, new technologies and new teaching methods in higher education mean that very different visual tasks are performed in the classroom, so further research is necessary to identify what lighting is best suited to these new tasks. The objective of the study is to analyse the impact that variations in levels of illuminance and Correlated Colour Temperature (CCT) of classrooms have on the cognitive functions (attention and memory) of university students. The cognitive performance of 90 participants was evaluated based on attention and memory tasks. The participants had to view nine virtual classroom configurations, with three different illuminance settings (100 lx, 300 lx and 500 lx) and three CCTs (3000 K, 4000 K and 6500 K). The results showed that attention and memory tasks require different level of illumination. While attention improves with higher light levels, memory improves with lower light levels. Higher CCTs generate better performance in both attention and memory tasks. These results highlight the link between lighting and students’ cognitive responses. This study and its methodology can be useful for architects and researchers as they establish lighting design guidelines capable of improving students’ cognitive processes. Full article

The evaluation of both visual and nonvisual effects from the spectral power distribution (SPD) of outdoor light is critical in lighting design. The dome-light SPD characteristically changes continuously depending on the seasonality, orientation, altitude of the sun or hour of the day. Traditional photopic parameters, such as the illuminance, luminance or correlated colour temperature (CCT), have been widely studied, but presently, there is no melanopic measurement or evaluation method. This article discusses the processes involved in establishing a simple method to determine the SPD of daylight and solar radiation over the skydome in a location to accurately account for the effects of both photopic and circadian levels around a location. Once per month for one year, natural daylight was spectrally measured in the city of Zaragoza (Spain); radiometric and photometric characteristics were analysed by season; and circadian effects were calculated in terms of standard parameters described by the Commission International de l’Eclairage (CIE), factors recommended by normative and scientific backgrounds. Finally, we suggest that the best parameter is the melanopic versus photopic irradiance ratio, which achieves reliable results at simplifying and correlating calculations. Full article

In the paper, the electrical and optical parameters of wirelessly controlled LED lamps of the Hue type are analysed. Features of this class of wirelessly controlled LED lamps given by the producer are described and a measuring setup for the electrical and optical parameters of the considered LED lamps is proposed. The results of measurements of the two investigated lamps with variable hue, based on RGB chips or emitted white light of different CCTs (correlated colour temperatures), are shown and discussed. Attention was given to the parameters characterising the influence of the tested LED lamp on such electric power quality indicators as PF (power factor) and THD (total harmonic distortion). Therefore, the influence of voltage supply and the selected value of power density of the emitted light on the THD and PF is analysed and discussed. Full article

The measurement of night sky quality has become an important task in night sky conservation. Modern measurement techniques involve mainly a calibrated digital camera or a spectroradiometer. However, panchromatic devices are still prevalent to this day, even in the absence of determining the spectral information of the night sky. In the case of multispectral measurements, colour information is currently presented in multiple ways. One of the most frequently used metrics is correlated colour temperature (CCT), which is not without its limitation for the purpose of describing especially the colour of natural night sky. Moreover, visually displaying the colour of the night sky in a quantitatively meaningful way has not attracted sufficient attention in the community of astronomy and light pollution research—most photographs of the night sky are post-processed in a way for aesthetic attractiveness rather than accurate representation of the night sky. The spectrum of the natural night sky varies in a wide range depending on solar activity and atmospheric properties. The most noticeable variation in the visible range is the variation of the atomic emission lines, primarily the green oxygen and orange sodium emission. Based on the accepted models of night sky emission, we created a random spectral database which represents the possible range of night sky radiance distribution. We used this spectral database as a learning set, to create a colour transformation between different colour spaces. The spectral sensitivity of some digital cameras is also used to determine an optimal transformation matrix from camera defined coordinates to real colours. The theoretical predictions were extended with actual spectral measurements in order to test the models and check the local constituents of night sky radiance. Here, we present an extended modelling of night sky colour and recommendations of its consistent measurement, as well as methods of visualising the colour of night sky in a consistent way, namely using the false colour enhancement. Full article

Illuminance levels have been standardized and regulated for many purposes. However, the effects of correlated colour temperature of lighting have received little attention in the field. This study investigated the effects of correlated colour temperature of lighting on the brightness sensation, lighting perception, and cognitive performance of 60 students under ambient light emitting diodes (LED) lighting conditions (CCT: 3000 K, 4000 K, and 5700 K; illuminance: 650 lx and 1050 lx) in an actual university classroom. An increase in correlated colour temperature (CCT) led to an increase in brightness sensation. However, increased CCT did not linearly increase lighting comfort. A CCT of 4000 K was considered as the optimum for lighting comfort in educational settings. But in comparison to comfort, higher levels of perceptual properties, satisfaction and acceptance were not affected by CCT from 3000 K to 5700 K. Scores on the working memory test were significantly affected by CCT and illuminance level in men only. The effects of gender appeared in glare sensation and the working memory test. Women were sensitive to glare sensation and had a lower mean score in the working memory test than men. Optimal CCT is more beneficial than increased illuminance in moderately ambient indoor lighting, as it provides better lighting comfort. Further research can look at the long-term effects of CCT on lighting perception depending on brain processing levels and more diverse and in-depth cognitive performance. Full article

This paper mainly studies the effect of artificial lighting environmental factors on the psychological emotions of observers in the large and practical space of the museums. The purpose is to reveal the relationship between the observers’ response and the artificial lighting condition in the actual art museum space. Field research regarding three art museums in Japan was carried out and the optical environment parameters applied in those museums were quantified. The innovation method is to define the artificial lighting environment space in the way of classified lighting design. Thirty one observers were invited to evaluate the three art museum’s lighting environment. In addition, this paper analyzes and discusses the influence of the actual spatial lighting parameters of museum buildings on observers’ psychological emotions (comfort, clarity, preference and warmth), under three modes of illuminance and correlated colour temperature (CCT) combination. Using one-way analysis of variance and correlation analysis, through analysis get the correlation of the four evaluation and three lighting environments indexes are less than 0.05, the observer in an environment with high illuminance and a high CCT had higher psychological evaluation of the art museum. Full article