Considerations of HUMAN FACTORS in lighting design
- 2. What do we know about WAVES?
- 7. Agenda Biology of the eye and light perception Light and Health / effects of light on the body Circadian Rhythms Seasonal Affective Disorder (SAD) Light Therapy Glare Light and the Elderly Lighting in Ergonomics Design Considerations for human factors
- 12. Lighting is Important to our Health Different colour temperatures of light effect our physical and psychological well-being Colours at sunrise and sunset cue our bodies to become more alert or more sleepy Because we typically use artificial light to guide our activities, we have grown out of touch with nature. Lack of sunlight or too much of it- can cause problems with circadian rhythms and mood
- 15. Physiological response of the eyes to light: Eyes respond to light by seeing things and creating visual effects, and also in unconscious ways that affect our bodies and minds, impacting our health and well-being. 3 types of photoreceptors detect light: rods and cones: form most of our vision for colours, shapes and movement vision The third class of photoreceptors (ipRGCs) express melanopsin biological processes Photosensitive, like plants- cellular process turns light into electrical signals. Responds most strongly to blue light syncs our circadian rhythm with the 24-hour solar day.
- 17. Circadian Rhythms Light-Dark Cycle: The natural daily shift of light, over 24 hours, is the major Zeitgeber (time-keeper) for all organisms. All species exhibit daily changes in their behavior and physiology according to a timekeeping system that reacts to changes in light. Circadian rhythms regulate sleep-wake behavior, hormone secretion, cellular function, and gene expression.
- 19. Chronobiology investigates biological rhythms - predominantly those that correspond to environmental cycles (tidal, daily, lunar, annual). The most intensively investigated biological timing system is the circadian clock These systems are so important that increasing evidence shows their disruption can lead to certain cancers, metabolic dysfunction, and mood disorders.
- 20. Disruption To Our Natural Rhythms Invention of artificial Light was a game changer Increase in mood disorders Synchrony is critical to our well-being and survival Lack of synchrony might lead to immediate health problems Long-term problems are still being researched, such as cancer, dementia, and some autoimmune diseases.
- 21. Biology and Colour The color temperature of daylight varies with the time of day, and can change significantly with altitude, latitude, season, and weather conditions. 2,000 K at sunrise and sunset 3,500 K "golden hour= the hour right after sunrise/ just before sunset 5,500 K at midday. Its important to consider the changes in light colour through the day since different wavelengths effect our physiology differently.
- 22. Different wavelengths (colours) may create the same visual impression, but these effect the circadian clock differently: Research has shown that high frequency (blue) light increases cortisol, serotonin and dopamine levels so boosts alertness, helps memory and cognitive function and elevates mood. Blue light suppresses the hormone melatonin, which is required for wound healing and sleep. Lack of proper sleep can cause a host of physical and psychological effects Some studies have shown that Red Light boosts physical performance, speeds muscle recovery, helps the body function more efficiently, and improves blood circulation. Some studies have shown that Green Light effects skin repair/collagen Lots of theories, many claims, current research bringing more truth to light!
- 23. Lighting influences mood in several ways: Brighter light makes us more alert and noisier, dimmer light makes us more relaxed. Over-lighting can make one feel anxious if its in an environment where one expects to be relaxed Colour Temperature (K) influences our mood because of our personal taste as well as our biology. Light directly modulates the availability of neurotransmitters such as serotonin, cortisol, dopamine, melatonin Patterns of light affect mood Uniform patterns = business-like Non-uniform patterns = relaxing and homey
- 25. Seasonal Affective Disorder (SAD) Symptoms of SAD include: Feeling depressed most of the day, nearly every day Losing interest in activities you once enjoyed Having low energy Having problems with sleeping Experiencing changes in your appetite or weight Feeling sluggish or agitated Having difficulty concentrating
- 26. Light Therapy In the last decades, light as an intervention has found an increasingly widespread use for treating mood and other psychiatric disorders Light entrains and stabilises circadian rhythms, thereby addressing desynchronisation and sleep disorders. Light therapy is a common treatment method for SAD. Its purpose is to mimic natural (outdoor) light, which has proven to cause changes in the brains chemicals, thus impacting mood.
- 30. Psychology of Colour How does this colour make you think and feel?
- 34. How does this colour make you think and feel? Psychology of Colour
- 36. Visual Comfort comprises several components The physical aspect of visual comfort: Being connected to nature, light quality, brightness and absence of glare. Numerous scientific studies have shown that working in an office with a view compared to a windowless office have positive impacts on mood and satisfaction. The psychological aspect of visual comfort: Studies have shown that light influences our bodies and minds. Light influences our health and well being through autonomic systems of the body. The socio-psychological aspect of visual comfort: Everyone has a different background and culture that shapes the way we appreciate light and visual environments. Thus, we have preferences in colour temperature and brightness.
- 37. Lighting is Part of Ergonomics Ergonomics is the science of work. the study of people in their working environment. Designers and specialists such as ergonomists create and arrange workplaces, products, and systems so that they fit the people that use them. The goal is to eliminate discomfort and risk of injury due to work. The modern holistic definition includes environmental ergonomics.
- 39. 3 Design Concepts in Environmental Ergonomics: Noise Lighting Climate
- 40. Visual discomfort and glare Visual discomfort can have various root causes, alone or in combination. Too little or too much illuminance Strong illuminance contrasts Distracting light patterns Flicker or stroboscopic effects (aka temporal lighting artefacts)
- 41. Glare Glare is a visual sensation caused by excessive and uncontrolled brightness in the field of view, that is more than what the eye can adapt to. Glare limits a persons ability to distinguish details and objects. Sensitivity varies between people, and older people are more sensitive to glare due to ageing of the eye.
- 42. Types of Glare some are subtypes, but there are many ways to categorize it Discomfort Glare Disability Glare Direct Glare Reflected/Indirect Glare Veiling Reflections Overhead glare
- 43. Direct glare This is caused by light sources such as candles, artificial lights with exposed lamps, windows, headlights and other sources of light that directly hit the eye and cause a detectable flare. Indirect glare Even if the light source itself can not be seen by the observer, reflective or glossy objects can cause bright splotches that act as indirect sources of light. A further differentiation may be made into: Reflected glare: The patches are so bright that they create discomfort Veiling reflections: Patches reduce the contrast and visibility of the object Classified by the cause of the glare sensation
- 45. Disability glare impairs the vision of objects without necessarily causing discomfort. Discomfort glare Results in an instinctive desire to look away from a bright light source. It is distracting or uncomfortable but does not significantly reduce the ability to actually see information needed for activities. Prolonged exposure to such conditions can result in headaches and eye fatigue. Classified by its effect on people
- 46. Discomfort glare can come from a direct or indirect source, like an overhead light (overhead glare) or a bright window beside a less bright desk
- 49. HOW TO CONTROL GLARE Consider the geometry of light and the task area. Limit the luminance of any light source in the direction of the eye. Re-position the work-station so that the glare source is not in the field of view. Do not illuminate the area surrounding the task more than the task itself. Screen the light source from view. Eliminate reflections on the monitor by considering angles of light incidence. If the person at work can see a light source reflected, then there is likely to be reflected glare.
- 51. Target Illuminance / Ages Standard Age Range is 40-55 years old Less than 40 years old Over 55 years old Can reduce the light levels up to 1/3! Can increase the light level up to 2/3!
- 52. Aging population is growing, expected to double by 2030 The elderly are more dependent on their environment Lots of government spending on long term care facilities (expected to increase by 75% over the next 15 years) The elderly require 25-50% higher illumination levels and special attention to quality bright, appropriate direction, good contrast, good colour rendering Considerations about the elderly
- 53. What Occurs to our Vision as we Age Pupils become smaller- less light can get in- more light required Lenses become denser Lenses yellow Decreased elasticity Floaters
- 54. Resulting in diseases and disorders of the eye such as: Degenerative myopia Cataracts Retinal detachments Retinopathy of prematurity (ROP) Glaucoma Optic nerve atrophy Albinism Aniridia Nystagmus
- 55. Cataracts In a healthy eye, the lenses are primarily crystal clear and flexible. As you age, the lenses become less flexible and cloudy areas typically cover the entire lens inside your eye. This is what happens when you develop cataracts. Approximatey 50% the population will develop cataracts by age 75. The earliest signs of cataracts include cloudy or blurred vision, poor night vision, and colors may not appear as vivid as they once did.
- 57. Increased sensitivity to glare Due to slow adaptation times, they are Especially sensitive to Blinding Glare = Glare that is so intense that for an appreciable length of time after it has been removed, no visual perception is possible
- 58. Consequences of aging eyes: Reduced visual acuity
- 59. special care required at transition areas Increased time for adaptation
- 62. Thus designers must ensure that lighting for the aged : Is sufficient quantity- extra bright Provides good contrast Assists with directions- entrances and hallways Is Non-glaring Is Non-flickering
- 64. Lighting, done well, can reinforce subjective effects such as: VISUAL CLARITY: Bright and uniform, with some peripheral emphasis SPACIOUSNESS: Uniform wall washing RELAXATION: Non-uniform lighting, emphasis on peripheral lighting and not overhead PRIVACY/INTIMACY: Non-uniform lighting, low intensity in specific area(s) MOODY/MYSTERIOUS: lighting from below to create shadows, low lumen lighting, PLEASANT: Non-uniform lighting, peripheral (wall) emphasis
- 65. Colour, Brightness & Spaciousness Brightness is directly related to the lightness of surrounding colours (Not necessarily whether it's warm or cool.) Lighter colours of objects reflect more light than darker and deeper colors, which brightens the room. Darker colours of objects absorb more light, and thus the overall effect is that the room is darker, too. Warm Colours: Appear to be approaching us. Cool Colours: Seem to recede from us.
Editor's Notes
- #2: As frequency increases wavelength decreases As frequency decreases wavelength increases
- #3: Visible light is just a small portion of what is known as The electromagnetic spectrum. This consists of all the different wavelengths of electromagnetic radiation, including light, radio waves, and X-rays. The only region in the entire electromagnetic spectrum that our eyes are sensitive to is the visible region. Radio wavesare b/w 1 mm and 100 km. Since these are the longest waves, they have the lowest energy and are associated with the lowest temperatures. Radio wavelengths are found everywhere. RADIO IS NOT CREATED FROM SOUND WAVES! Radio stations use radio wavelengths of electromagnetic radiation to send signals that our radios then translate into sound. Radio stations transmit electromagnetic radiation, not sound. The radio station encodes a pattern on the electromagnetic radiation it transmits, and then our radios receive the electromagnetic radiation, decode the pattern and translate the pattern into sound. Infrared wavelengthsspan from 710 nm 1 millimeter (from the width of a pinpoint to the size of small plant seeds). At a temperature of 37 degrees C, our bodies give off infrared wavelengths with a peak intensity near 900 nm. Visible lightcovers the range of wavelengths from 400 700 nm (from the size of a molecule to a protozoan). Our sun emits the most of its radiation in the visible range, which our eyes perceive as the colors of the rainbow. Our eyes are sensitive only to this small portion of the electromagnetic spectrum. Ultraviolet radiationhas wavelengths of 10 310 nm (about the size of a virus). Young, hot stars produce a lot of ultraviolet light and bathe interstellar space with this energetic light. X-raysrange in wavelength from 0.01 10 nm (about the size of an atom). They are generated, for example, by super-heated gas from exploding stars and quasars, where temperatures are near a million to ten million degrees. Gamma rayshave the shortest wavelengths, < 0.01 nanometers (about the size of an atomic nucleus). This is the highest frequency and most energetic region of the electromagnetic spectrum. Gamma rays can result from nuclear reactions and from processes taking place in objects such as pulsars, quasars, and black holes.
- #8: Light is healthy, it makes us feel good. Thus as designers creating environments that feel good in artificial lighting should also be a priority Human perception and culture influence our preferences But overall there are biological and psychological processes resulting from light that are true for all of us When light biologically impacts us, it can improve or disrupt our sleep, cognition and overall wellbeing. It can improve mood and stabilize our circadian rhythms, helping us get a better and deeper nights sleep. Light can decrease depression scores and even increase cognitive performance such as reaction time and activation.
- #9: Light is healthy, it makes us feel good. Thus as designers creating environments that feel good in artificial lighting should also be a priority Human perception and culture influence our preferences But overall there are biological and psychological processes resulting from light that are true for all of us When light biologically impacts us, it can improve or disrupt our sleep, cognition and overall wellbeing. It can improve mood and stabilize our circadian rhythms, helping us get a better and deeper nights sleep. Light can decrease depression scores and even increase cognitive performance such as reaction time and activation.
- #10: Focus is on human needs today, and how lighting can satisfy and enhance our needs
- #11: The physical aspect of visual comfort:Being connected to nature, light quality, brightness and absence of glare. Numerous scientific studies have shown that working in an office with a view compared to a windowless office have positive impacts on mood and satisfaction. The psychological aspect of visual comfort:Studies have shown that light influences our bodies and minds. Light influences our health and well being through autonomic systems of the body. The socio-psychological aspect of visual comfort:Everyone has a different background and culture that shapes the way we appreciate light and visual environments. Thus, we have preferences in colour temperature and brightness.
- #13: https://www.urban-health.eu/index.php/2021/09/09/international-conference-shaping-light-for-health-and-wellbeing-in-cities-16th-and-17th-december-2021-2/ Artificial light has changed society Before the invention of the light bulb, our circadian rhythms were well in sync with the sun, because nighttime light disruption was minimal. But all this use of light during the nighttime has put us out of touch with nature, and our natural rhythms.
- #14: https://youtu.be/GbHGRMv7rDE 5 minutes Light and health
- #15: (Intrinsically photosensitive retinal ganglion cells
- #16: Light enters the eye and is transmitted unconsciously to the brain through the SCN, the bodys master internal clock. Whether blind or seeing, ALL mammals have an autonomic response to the changes of light throughout the day. This biological clock allows us to anticipate and prepare for the changes in the physical environment associated with day and night, ensuring that we receive bodily signals to do what our bodies need at the right time of the day.
- #17: Q: What are some of the bodily processes that work on an automatic schedule? What signals do you receive from your body to take care of yourself?
- #19: Behaviour, physiology, bio-chemistry, and gene expression are temporally structured over the course of a day,
- #20: 1- Before the invention of the light bulb, our circadian rhythms were well in sync with the sun, because there was no nighttime light disruption of nature. 2. We are only now beginning to understand the correlation and causation between the increase in nighttime lighting and the increase in mood disorders 3. 4. Llack of synchrony with the environment can lead to health probs such as impaired cognitive function, attention deficits, altered hormonal function, and gastrointestinal complaints
- #22: I started studying this topic about 20 years ago for my design thesis, and since then there has been even more discovered, e.g. the melanopsin receptors
- #23: Whether its a direct connection or indirect due to rhythms, we know that light makes a difference in how we feel and function
- #24: SAD is a mood disorder that is caused by symptoms of depression during certain times of the year, usually during the winter. Its not exclusive to people who have a history of mental illness and can happen to anyone. Some geographic locations have more cases of SAD than others due to the differences in the seasons.
- #25: Mayoclinic.com
- #26: There are many types of light boxes that can be utilized, but essentially, you are exposed to a bright light within the first hour of waking up every day.
- #32: red
- #34: green
- #39: LIGHTING IS NOT ONLY ABOUT CREATING A LOOK- ITS ALSO IMPORTANT CONSIDERATION FOR PRODUCTIVITY AND PHYSICAL WELL BEING Just like a specific geometry is best for desk work, so is a certain light
- #40: Ergonomics have expanded to include many facets beyond a good hand grip, desk chair or physical layout. The modern holistic definition includes environmental ergonomics.
- #46: Veiling reflections examples- click
- #49: Philipps video about GLARE
- #50: Name the kind of glare- click
- #52: Check time- if before 5 go to daylighting
- #53: Babies require 3x more light than 20 yr olds
- #55: Degenerative myopia Cataracts Retinal detachments Retinopathy of prematurity (ROP) Glaucoma Optic nerve atrophy Albinism Aniridia Nystagmus
- #57: https://www.goodeyes.com/blog/6-common-eye-diseases-that-develop-with-age/
- #66: Disagree with COLD use for brainstorming sure ok with groups in an office, but not conducive to creativity. Dim lighting best for creative juices to flow. creativity thrives in the dark, careful reasoning flourishes in the light. a well-designed workspace must adapt to what youre working on Apparently, darkness triggers a chain of interrelated processes, including a cognitive processing style, which is beneficial to creativity, the researchers concluded in theSeptember issueof theJournal of Environmental Psychology. General rule: cool light during the day, warm light at night
- #68: Light Colours: Think WHITE- reflects all colours, therefore reflects lots of light INTO a room To brighten a room that has limited daylight, use light colours, such as pastels. Dark Colours: Think about BLACK- absorbs all colours, therefore less light available To tone down a room that gets a lot of light, or to simply add contrast to the brightness, look to darker colours, whether warm or cool. To make a small room seem bigger, wall wash onto cool pastels It is a generally known fact that light colorsmakearoom look biggerand brighter. Light and bright walls are more reflective,makinga space feel open and airy, which helps maximize the effect created by natural light. Dark colors, on the other hand, tend to absorb light,makingaroom looksmaller. Trypainting your wall trim and moldings in a lighter color than your walls. By doing so, the walls will appear farther back, making your living room seembigger.
- #69: Cool colours make the room calm and seem more spacious than it is
- #70: Warm colours make the big room feel cozy and more intimate