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In her 2012 talk, Wendy Davis, Associate Professor and Director of Illumination Design, explores the fundamental reasons behind our lighting choices. She challenges the status quo of merely meeting energy standards, budgets, and technology limitations. Instead, Davis emphasizes that we light environments to enhance visibility for people, showcasing art, architecture, and intimate interactions. Furthermore, she discusses moving past the traditional incandescent lamp to embrace innovative lighting solutions that prioritize color rendering and spatial distribution. This vision aims to redefine how we approach lighting, focusing on human experience and environmental impact.
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Shifting Our Vision for Lighting Lux America 2012 Wendy Davis Associate Professor Director Illumination Design
Why do we light? • We do not light to: • Expend / save energy • To meet standards & building codes • To meet budgets • To use particular technologies Image from: http://rabbishishler.blogspot.com.au/2012/02/soul-budget.html Image from: http://www.csiro.au/en/Outcomes/Energy/Saving-energy-in-your-home.aspx Image from: http://nyack-ny.gov/departments/building/
Why do we light? • We light so that people can see: • Books • Faces • Artwork • Stairways • Etc. Image from: http://www.autism-community.com/a-plethora-of-literacy-resources/ Image from: http://www.guardian.co.uk/world/2010/nov/25/ernest-cole-david-goldblatt-apartheid-photography Image from: http://www.optforhealthyliving.org/
Fixation with the incandescent lamp The ways we measure, evaluate and communicate about lighting are technology-focused & backward-looking Image from: http://cheaptalk.org/2011/03/18/backward-and-forward-looking-organizations/
Correlated colour temperature (CCT) + Duv - Duv
Colour rendering index (CRI) Reference illuminant Test source CIE Dxx Same CCT [K] Planckian (CCT<5000 K) Standard Daylight (CCT > 5000 K) #1 #2 #3 #4 #5 #6 #7 #8 Ra #9 #10 #11 #12 #13 #14
Colour rendering index (CRI) = perfect?
Colour rendering index (CRI) Neodymium incandescent lamp CRI = 77 (normal incandescent lamp CRI=100) Image from: http://www.ge.com/innovation/timeline/eras/breakthrough_discoveries.html Ref. LED
Colour rendering index (CRI) 3-LED Model Peaks at: 464, 538, 620 nm CRI = 63 Image from: http://glassbox-design.com/2009/elos-rgb-led-prototype-changes-colors-on-demand/ Ref LED
Further complications Hunt Effect Colorfulness / saturation increases with luminance
Moving beyond the incandescent Image from: http://www.eralight.biz/led-bulb/e27-led-bulb.html Image from: http://www.alibaba.com/product-gs/303496832/F96T12_replacement_LED_tube.html • Retrofits / replacement lamps: • Minimal consumer investment • Compatible with existing infrastructure • Reversible
Moving beyond the incandescent Image fromhttp://news.cnet.com/8301-11386_3-57428951-76/philips-led-replaces-100-watt-incandescent/ Image from: http://elektro-vault.blogspot.com.au/2012/06/27w-led-to-replace-100w-bulb.html • Retrofits / replacement lamps: • Difficult to engineer • Fail to capitalize on benefits of newer technologies • Presume incumbent technologies are optimal
Moving beyond the incandescent 1http://elearningfacultymodules.org/index.php/E-Learning_Terminology Disruptive technology “A new technology that changes the current way of approaching a particular problem or issue”1 Images from: Wikipedia Commons
Moving beyond the incandescent Let’s imagine… Image from: http://www.canstockphoto.com/illustration/imagine.html
How far could we go? Image from: http://www.cnet.com.au/apple-iphone-4-339303698.htm Image from: http://johngushue.typepad.com/blog/2010/06/technology.html Image from: Wikipedia Commons Image from: http://dekhomobile.blogspot.com.au/2011/11/latest-glass-mobile-phone-latest-mobile.html
How do we get there? Image from: http://www.guardian.co.uk/voluntary-sector-network/2012/jun/13/charity-conduct-strategic-review-advantages
Principle of Univariance • The cones transmit no spectral information • Countless different spectra can lead to identical patterns of cone activity • Perceptions of colour arise from combining and comparing the activity of the different cone classes
Colour matching functions x(λ) r(λ) y(λ) g(λ) z(λ) b(λ)
Colour matching functions • x + y + z = 1 • (x, y) is a 2-dimensional representation of chromaticity. • Y is a measure of visual intensity of light stimulus. • x, y, Y fully describe light stimulus.
Colour opponency Image from: http://facweb.cs.depaul.edu/sgrais/color_perception.htm
Colour opponency blue red red green yellow DeValois & DeValois (1993)
Moving beyond the incandescent Metamers
Luminous efficacy Luminous efficacy = radiant efficiency x luminous efficacy of radiation (LER) LER = 154 lm/W LER = 408 lm/W
Colour rendering Four lasers Image from: Wikipedia Commons
Object reflectance Image from: http://greatfruitpictures.onsugar.com/Orange-Fruit-Picture-18993899
Visual processing blue red red green yellow DeValois & DeValois (1993)
Moving forward • Spectral design & colour properties • Size & shape of lighting products • Spatial distribution of light • Modes of control & human interaction • … Image from: http://gooddisruptivechange.com/why-change-your-mindset/