Daily indoor light exposure: A spectral analysis of ambient light sources and its relevance to occupational dermatology

Introduction: To uncover a relationship between light exposure and myopia is complicated because of the challenging nature of measuring visually relevant illumination experienced by children. Objective: To find a methodology to measure face illuminance using a mobile device. Methods: Accuracy and precision of the mobile device’s built-in ambient light sensor were tested under three different lighting conditions: full-field, a single small light, and one mimicking typical office illumination. Face illuminance was computed in six faces with different skin reflectances using pixel values in face images captured by the device camera placed at 30 cm in front of the face. The results were compared with those obtained with a commercial light meter situated at the face. Results: The illuminance measured by the device’s ambient light sensor showed high linearity (R2 > 0.99) slightly under-estimating or conversely over-estimating face illuminance with full-field or single light sources but accurate for office lighting. Face illuminance measured by the devices’ camera under indoor conditions using the new methodology showed a mean relative error of 27% and a high linearity (R2 > 0.94). Conclusions: Introduction of an app can be used to assess the association between visually relevant environmental light levels and myopia progression.

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Interim Report on THE LIGHTFASTNESS CORRELATION PROJECT

MRS Proceedings ◽

10.1557/opl.2011.795 ◽

2011 ◽

Vol 1319 ◽

Author(s):

Mark D. Gottsegen

Keyword(s):

Western Europe ◽

Color Change ◽

Light Exposure ◽

Extended Period ◽

Test Sample ◽

Test Methods ◽

Light Sources ◽

Initial Development ◽

Color Changes ◽

Single Number

ABSTRACTThis paper describes the five-year Lightfastness Correlation Project that I am conducting in sixteen institutions in the US and Western Europe, with the support of the Samuel H. Kress Foundation.Dr. Robert L. Feller, a scientist at the National Gallery of Art, published several papers in the 1970s in which he speculated that a certain duration of time could be correlated, in a general way, to the color changes noted in the Blue Wool Textile Fading Cards. Museums use the cards as inexpensive dosimeters, put somewhere in a gallery along with the art. Enough is known about their behavior to have confidence in their ability to indicate when it is time to remove an object from exhibition.The Blue Wools are also used in two Standards developed by ASTM International’s Subcommittee D01.57 on Artists’ Paints and Related Materials. ASTM D 5383 and ASTM D 5398 are simple lightfastness test methods. In them, the Blue Wool cards are exposed to natural daylight along with any colored material, and are used to tell the artist when it’s time to stop the test and as a rating device.Another ASTM Standard from D01.57, ASTM D4303, uses instruments to control the accumulated amount of natural daylight, or simulated daylight in a xenon arc light exposure machine. It also uses a spectrophotometer to calculate the color change that can occur in a test sample, expressed in CIE L*a*b*. There is also a standard formula for calculating color change that results in a single number, expressed as Delta E, or ∆E.The ∆E number is used by ASTM D01.57 to assign lightfastness ratings to artists’ coloring materials covered by its Specifications for various products. Initial development of the ASTM methods began in 1977; we have 33 years of data that confirms the worth of the methods used in our testing.What is the relationship between the results of Blue Wool testing and the results using D01.57’s technical ∆Es? This is a fundamental question we have yet to thoroughly examine. We have begun to work on the problem, using accelerated natural and artificial light sources as in ASTM D 4303. But no one has ever tried to compare the results of these two test methods in a museum environment, over an extended period of real time.“The Lightfastness Correlation Project” ends in August 2011, and a final scientific report will be submitted to the sponsor, The Samuel H. Kress Foundation, in September 2011.

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Effect Of Chromaticity Of Surrounding Light Sources on Mesopic Adaptation Luminance

Light & Engineering ◽

10.33383/2020-012 ◽

2021 ◽

pp. 30-38

Author(s):

Sangita Sahana ◽

Biswanath Roy

Keyword(s):

Light Source ◽

The State ◽

Light Sources ◽

Ambient Light ◽

Lighting Conditions

This paper presents variations in mesopic adaptation luminance in the presence of ambient light sources along with main light source for outdoor lighting applications. Mesopic photometry system is based on peripheral task, and adaptation luminance is required to compute the effective mesopic radiance for the measured area. Different lighting conditions were considered to determine the effect of chromaticity of bright surrounding sources other than the main light sources to the state of observer adaptation. The veiling luminance caused by the surrounding sources increases the state of observer adaptation, but not the luminance within the measurement field. It has also been observed that in case of cool white surrounding sources, adaptation luminance increases significantly than that of warm white sources.

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Flash and ambient light exposure

Outdoor Flash Photography ◽

10.4324/9781315719627-5 ◽

2017 ◽

pp. 47-61

Keyword(s):

Light Exposure ◽

Ambient Light

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Light Emitting Diodes (LED) for Aqueous Light Bleaching of Paper

Restaurator International Journal for the Preservation of Library and Archival Material ◽

10.1515/res-2018-0022 ◽

2019 ◽

Vol 40 (2) ◽

pp. 69-95

Author(s):

Benjamin Kirschner ◽

Irene Brückle ◽

Ute Henniges

Keyword(s):

Carbonyl Group ◽

High Performance ◽

Molar Mass ◽

Light Exposure ◽

Light Sources ◽

Light Emitting ◽

Colour Temperature ◽

Negative Effect ◽

Hid Lamps ◽

Reference Samples

Abstract High performance daylight LED lamps are compared with HID lamps for light bleaching of paper. The LED can be placed in closer proximity to the object than the HID lamps, causing a significantly increased, uniform light exposure. Two commercial LED systems with 4000 K and 6500 K colour temperature were installed in a convertible test device with a polypropylene tray in default exposure distance of 10 cm and 20 cm. A HID lamp in 60 cm and 120 cm distance served as a reference. Samples of two naturally aged rag papers were bleached with both LED systems and with the HID while immersed in water. All three light sources increased brightness (CIELAB L*), though the LEDs with 4000 K colour temperature were most effective. They had no negative effect on the molar mass and the cellulose carbonyl group content while LEDs with 6500 K colour temperature caused molar mass decrease and carbonyl group increase. LEDs of a 4000 K or similar colour temperature are a promising option for improved light bleaching of paper, reducing the treatment and aqueous exposure time and eliminating UV radiation.

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Circadian Potency Spectrum with Extended Exposure to Polychromatic White LED Light under Workplace Conditions

Journal of Biological Rhythms ◽

10.1177/0748730420923164 ◽

2020 ◽

Vol 35 (4) ◽

pp. 405-415 ◽

Cited By ~ 1

Author(s):

Martin Moore-Ede ◽

Anneke Heitmann ◽

Rainer Guttkuhn

Keyword(s):

Spectral Sensitivity ◽

White Light ◽

Light Exposure ◽

Human Subjects ◽

Light Sources ◽

Led Light ◽

Light Spectra ◽

Timing System ◽

Circadian Timing System ◽

Spectral Sensitivity Curve

Electric light has enabled humans to conquer the night, but light exposure at night can disrupt the circadian timing system and is associated with a diverse range of health disorders. To provide adequate lighting for visual tasks without disrupting the human circadian timing system, a precise definition of circadian spectral sensitivity is required. Prior attempts to define the circadian spectral sensitivity curve have used short (≤90-min) monochromatic light exposures in dark-adapted human subjects or in vitro dark-adapted isolated retina or melanopsin. Several lines of evidence suggest that these dark-adapted circadian spectral sensitivity curves, in addition to 430- to 499-nm (blue) wavelength sensitivity, may include transient 400- to 429-nm (violet) and 500- to 560-nm (green) components mediated by cone- and rod-originated extrinsic inputs to intrinsically photosensitive retinal ganglion cells (ipRGCs), which decay over the first 2 h of extended light exposure. To test the hypothesis that the human circadian spectral sensitivity in light-adapted conditions may have a narrower, predominantly blue, sensitivity, we used 12-h continuous exposures of light-adapted healthy human subjects to 6 polychromatic white light-emitting diode (LED) light sources with diverse spectral power distributions at recommended workplace levels of illumination (540 lux) to determine their effect on the area under curve of the overnight (2000–0800 h) salivary melatonin. We derived a narrow steady-state human Circadian Potency spectral sensitivity curve with a peak at 477 nm and a full-width half-maximum of 438 to 493 nm. This light-adapted Circadian Potency spectral sensitivity permits the development of spectrally engineered LED light sources to minimize circadian disruption and address the health risks of light exposure at night in our 24/7 society, by alternating between daytime circadian stimulatory white light spectra and nocturnal circadian protective white light spectra.

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The Effect of Light on Sleep and Sleep-Related Physiological Factors Among Patients in Healthcare Facilities: A Systematic Review

HERD Health Environments Research & Design Journal ◽

10.1177/1937586719827946 ◽

2019 ◽

Vol 12 (4) ◽

pp. 116-141

Author(s):

Khatereh Hadi ◽

Jennifer R. Du Bose ◽

Young-Seon Choi

Keyword(s):

Light Exposure ◽

Bright Light ◽

Light Sources ◽

Related Factors ◽

Healthcare Facilities ◽

New Findings ◽

Healthcare Environments ◽

The Impact ◽

Improve Patient ◽

Bright Light Exposure

Objectives: Lighting is one of the environmental factors which can improve patient sleep in healthcare environments. Due to the high degree of variation in study designs and results on this topic, the implications have been difficult to interpret. This review consolidates studies on the impact of bright light exposure on sleep to identify lighting conditions that can be applied and researched in future healthcare environments. Methods: We searched for peer-reviewed articles on the impact of light on sleep or sleep-related outcomes in healthcare settings. We provided detailed analysis of the direct links between light and sleep, and a more cursory analysis of links between light and sleep-related factors, from 34 articles which met our inclusion criteria. Results: The current state of the literature includes evidence on how various durations and intensities of morning, midday, and evening bright light exposure, as well as whole-day light exposure interventions can improve specific aspects of sleep. Lighting interventions differed in all attributes (illuminance levels, exposure time, exposure duration, and spectral qualities) but showed promising results in improving patients’ sleep. Conclusions: Short-term bright light exposure in the morning, up to 2 hr of moderate (3,000–10,000 lux) morning exposures, up to 4 hr of moderate evening exposure, and whole-day exposures to lower illuminance levels (<3,000 lux) can improve patient sleep outcomes. Based on new findings on the mechanism through which light impacts sleep, future studies should be more specific about the spectral qualities of light sources.

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Light and diel vertical migration: spectral sensitivity and light avoidance by Mysis relicta

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f98-174 ◽

1999 ◽

Vol 56 (2) ◽

pp. 311-322 ◽

Cited By ~ 44

Author(s):

Gideon Gal ◽

Ellis R Loew ◽

Lars G Rudstam ◽

Ali M Mohammadian

Keyword(s):

New York ◽

Vertical Migration ◽

Diel Vertical Migration ◽

Spectral Characteristics ◽

Human Vision ◽

Light Sources ◽

Ambient Light ◽

Mysis Relicta ◽

Light Levels ◽

Cayuga Lake

Ambient light levels determine the extent of diel vertical migration of many species including mysid shrimps. Light levels perceived by an organism depend on the intensity of light at the surface, the extinction of light through the water, and the sensitivity of the organism's light receptors. Each of these processes has spectral characteristics that should be taken into account when measuring perceived light levels. We used microspectrophotometry to determine that Mysis relicta has a single pigment with the characteristics of rhodopsin based on vitamin A1 and a peak sensitivity of 520 nm. Similar to the use of the lux (scaled to human vision), we give ambient light levels scaled to the mysid's visual spectrum in mylux units. Mysid distributions were observed with acoustics around two artificial light sources in Cayuga Lake, New York. Mysids avoided light levels of 3.4 × 10-7 to 2.1 × 10-6 mylux. Similar light levels limited their vertical distributions during the night in Lake Ontario and during the day in Cayuga Lake. Of standard light sensors available, lux meters are more appropriate than photosynthetically active radiation meters for determining light levels perceived by mysids.

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Lights, bats, and buildings: investigating the factors influencing roosting sites and habitat use by bats in Grand Teton National Park

The UW National Parks Service Research Station Annual Reports ◽

10.13001/uwnpsrc.2019.5693 ◽

2019 ◽

Vol 42 ◽

pp. 20-25

Author(s):

Hunter J. Cole ◽

Cory A. Toth ◽

Jesse R. Barber

Keyword(s):

National Park ◽

Large Scale ◽

Light Exposure ◽

Light Sources ◽

Street Lighting ◽

Grand Teton National Park ◽

Bat Activity ◽

Red Led ◽

Negative Impacts ◽

Mitigation Methods

Free-flying bats are highly affected by artificial night lighting, causing individuals to either 1) gather in unnaturally high densities around the light sources to exploit insects, or 2) travel increased distances to avoid light exposure. Similarly, nocturnal insects are disproportionately attracted to night lighting, trapping them until they die of exhaustion. The advent of new lighting technology which may decrease the impacts of night lighting on bats and insects by primarily producing light at wavelengths these animals are not sensitive to (i.e. in the red portion of the spectrum) is promising, however no studies have shown this at a large scale, and not in North America. Similarly, many studies on the effects of lights on bats, in general, have been on European species, and thus our overall understanding of how North American species are affected is low. Grand Teton National Park, Wyoming, provides an excellent natural system to study the effects of lights on bat behavior, as well as to test possible mitigation methods, as the park supports a large community of over a dozen species, as well as sizeable human infrastructure that generates night light. From June through September, 2019, we undertook a large-scale, blocked experiment examining bat activity and space use in Colter Bay Village under both traditional street-lighting, as well as new “bat friendly” street lighting. Using both passive echolocation records and radiotelemetry, we collected data that will allow us to examine the ability of red LED streetlights to mitigate artificial light’s negative impacts on bats and insects. Featured photo from figure 2 in report.

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Characterizing the modern light environment and its influence on circadian rhythms

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2021.0721 ◽

2021 ◽

Vol 288 (1955) ◽

pp. 20210721

Author(s):

Dennis Khodasevich ◽

Susan Tsui ◽

Darwin Keung ◽

Debra J. Skene ◽

Victoria Revell ◽

...

Keyword(s):

Circadian Rhythms ◽

Light Exposure ◽

Circadian Disruption ◽

Light Sources ◽

Night Time ◽

Circadian Phase ◽

Temperature Rhythm ◽

Four Seasons ◽

Significant Difference ◽

The Impact

Humans have largely supplanted natural light cycles with a variety of electric light sources and schedules misaligned with day-night cycles. Circadian disruption has been linked to a number of disease processes, but the extent of circadian disruption among the population is unknown. In this study, we measured light exposure and wrist temperature among residents of an urban area during each of the four seasons, as well as light illuminance in nearby outdoor locations. Daily light exposure was significantly lower for individuals, compared to outdoor light sensors, across all four seasons. There was also little seasonal variation in the realized photoperiod experienced by individuals, with the only significant difference occurring between winter and summer. We tested the hypothesis that differential light exposure impacts circadian phase timing, detected via the wrist temperature rhythm. To determine the influence of light exposure on circadian rhythms, we modelled the impact of morning and night-time light exposure on the timing of the maximum wrist temperature. We found that morning and night-time light exposure had significant but opposing impacts on maximum wrist temperature timing. Our results demonstrate that, within the range of exposure seen in everyday life, night-time light can delay the onset of the maximum wrist temperature, while morning light can lead to earlier onset. Our results demonstrate that humans are minimizing natural seasonal differences in light exposure, and that circadian shifts and disruptions may be a more regular occurrence in the general population than is currently recognized.

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