Light Sources Secondary Light Sources Eyes Brain Generators – Modifiers and Re-transmitters Receivers – Decoder – Transmitters Encoders Interpreter Sun, Discharge lamps, Atmosphere, Air, Water, Planets, Lenses, Cornea, Iris, Lens, Analysis, fluorescent lamps. Windows, Tress – All natural or manufactured Rods & Cones, Identification Incandescent lamps, objects which modify light waves before they Optic Nerves Association Open flames, etc. reach the eye. Perception 1 Controlling Light 2 Light = Color 3 What is Light? Light is a form of energy that is part of the electromagnetic spectrum visible to the human eye. 4 Light = Color 5 Color Mixing 6 Light = Color Colors by Addition Colors by Subtraction Mixture of Light Mixture of Pigments 7 What is Light? There are two different ways of talking about light: There is the "particle" theory, expressed in part by the word photon. There is the "wave" theory, expressed by the term light wave. 9 Light = Energy Waves 10 Light = Color Spectral Power Distribution Curves (SPD) provide the user with a visual profile of the color characteristics of a light source. They show the radiant power emitted by the source at each wavelength or band of wavelengths over the visible region (380 to 760 nm). 11 Light = Color Daylight at Noon Afternoon Sun Full Moon Tubular Candle Fluorescent Incandescent Compact Fluorescent 12 Metal Halide High Pressure Sodium (indigo nightlight) PC Monitor PC Laptop 13 Color Spectrum Night Morning Afternoon Late Afternoon Night Incandescent Lamps and Natural Daylight produce smooth, continuous spectra. 14 Daylight Color Spectrum Passenger (stills), video projection, 2004 Jutta Strohmaier For Passenger, Strohmaier photographed the same spot every minute for three days. “The private, insular room opens up to the outside world under certain light conditions, blurring the boundaries between the inner and outer worlds,” she explains. “It’s like looking out the window of an airplane – time and space pass by.” 15 Daylight Color Spectrum 16 Seeing Color http://www.gelighting.com/na/business_lighting/education_resources/learn_about_light/color_lamp.htm 17 Correlated Color Temperature color appearance of various light sources The higher the color temperature (CCT), the “cooler” the color of the lamp is in appearance. The lower the color temperature (CCT) the “warmer” the color the lamp is in appearance. This color temperature is measured in Kelvin. 2200 o 2700 o 4100 o 18 Correlated Color Temperature Kelvin Temperature Cool 9000 North Blue Sky 8500 8000 7500 7000 6500 Overcast Day Daylight Fluorescent Cool White 6000 Fluorescent Mercury 5500 Direct Sunlight 5000 4500 Metal Halide 4100K Fluorescent 4000 3500 3500K Fluourescent 3000K Metal Halide 3000K Fluorescent 3000 Warm White Halogen Fluorescent Incandescent 2500 Fire / Candle light High Pressure Sodium 2000 Warm 1500 Hot Embers 19 Light = Seeing Colors 20 Color Rendering Index how a light source renders the color of objects Comparing the colour appearance under different light sources (left); Test swatches under different light (right) The color rendering of a light source is an indicator for its ability of realistically reproduce the color of an object. Following the CIE (International Lighting Commission), color rendering is given as an index between 0 and 100, where lower values indicate poor color rendering and higher ones good color rendering. The color rendering of a light source is compared a continuous spectrum source, such as incandescent - to daylight if its CCT is >5000K. 21 Color Rendering Index how a light source renders the color of objects High CRI light makes virtually all colors look natural and vibrant. Low CRI causes some colors to appear washed out or even take on a completely different hue. 22 Basic Concepts for Illumination of 3d Objects Using warm and cool sources for Key and Fill light not only increases sense of shape and depth of an object, but assist with defining direction of light 25 Basic Concepts for Illumination of 3d Objects Using warm and cool sources for Key and Fill light not only increases sense of shape and depth of an object, but assist with defining direction of light Cool Light And Warm Shade: Color also can provide information about an object's dimensions and depth. Our visual system assumes the light comes from above, we rely on our visual experience with nature to explain direction of light “visual experience tells us warm light comes from the interior illumination, a cooler light source comes from nature – daylight at day, moonlight at night” 26 Alexander Hamilton US Customs House, NYC 27 Controlling Light 28 Light Direction Light travels in a straight line…radiates out from the source 29 Light Direction of Clear Lamps Light travels in a straight line…radiates out from the source …. add a clear enclosure or envelope around the source, the light will still travel in a straight line. 30 Light Direction of Frosted Lamps Light travels in a straight line…radiates out from the source …. add a coated or frosted enclosure or envelope around the source, the direction of light will bend and radiate from the surface of the enclosure 31 Light Performance Optics Absorption Reflection Light 100% 80% 80% The material absorbs 20% - reflects 80% Typical Materials: Metal Mirror Wood 32 Reflection Luminaires can shape light by reflection Reflectors finishes may be Specular – shiny, polished Semi-Specular Diffuse – dull, matte Light Source 33 Reflection Luminaires can shape light by reflection Reflectors may be Specular – shiny, polished Semi-Specular Diffuse – dull, matte Light Source 34 Reflection Light Source Incidence Reflectance Incidence = the light that enters Reflection = the light that exits For “specular” reflectors, the angle of incidence equals the angle of reflection 35 Light Performance Optics Absorption Transmission Light 100% The material absorbs 20% - transmits 80% Typical Materials: Glass Plastic Fabric 80% 80% 36 Light Technologies New Developments There was a need to improve the light several ways: 1. The need for a constant flame, which could me left unattended for a longer period of time 2. Decrease heat (and smoke) for interior use 3. To increase the light output 4. An easier way to replenish the source….thus, the development of gas and electricity 5. Produce light with little waste or conserve energy 38 Early Electric Light Technologies arc lamps early in the 19th century 39 Early Electric Light Technologies 40 Early Electric Light Technologies Edison and Swan: Developed the incandescent carbon filament lamp in late 1870s Edison designed a complete electrical system and a lamp that could be mass-produced 41 Electric Sources Light Fixture 42 Electric Sources LampBulb 43 Lamps 44 Electric Sources Lamps for General use 45 Electric Sources Lamps for General use INCANDESCENT DISCHARGE LAMPS (filament) LAMPS Incandescent Fluorescent High Intensity (HID) Linear Halogen Compact 46 Electric Sources - Lamps Solid State (LED) White Color Discrete (monochromatic, variable Kelvin) RGB Retrofit Tri-node 47 Electric Sources - Lamps Specialty Neon Electroluminescent 48 Lamps = Sources Points Blobs Lines 49 Points 50 Blobs 51 Lines 52 Lamp Shape Nomenclature 53 Lamp Shapes 54 How Incandescent Lamps Work 55 Points: General Purpose/ A-Lamps 56 Points: B, BA, C, CA, and F 57 Points: G – Lamps 58 Points: Specialty / T and S - Lamps 59 Points: Halogen Lamps 60 How Halogen Lamps Work Halogen Cycle 61 Transformer A transformer connects in between the line and the lamp Transformer are for low voltage lamps Remote Integral Transformer Transformer 62 Points: LED’s Light-emitting diodes (LEDs): Semi-conductor devices that have a chemical chip embedded in a plastic capsule 63 How LED’s Work 64 65 66 When the negative end of the circuit is When the positive end of the circuit is hooked up to the N-type layer and the hooked up to the N-type layer and the positive end is hooked up to P-type negative end is hooked up to the P-type layer, electrons and holes start moving layer, free electrons collect on one end of and the depletion zone disappears. the diode and holes collect on the other. The depletion zone gets bigger. The interaction between electrons and holes in this setup has an interesting side effect -- it generates light! 67 mms://Ntstream2.ddns.ehv.campus.philips.com/efi/86090/Lumali ve.wmv 68 LED 69 LED 70 LED http://www.colorkinetics.com/showcase/videos/target.htm http://www.colorkinetics.com/showcase/videos/wlf_04.htm 71 LED http://www.lif-germany.de/film/mov07793.mpg 72 73 74 75 738 modules 82 power supplies 76 77 78 Blobs 79 “Blob” Source Halogen Lamps 80 Reflection Rays are Parallel Parabola or Rays converge Parabolic Ellipse, Ellipsoidal, or Reflector 2 foci Elliptical Reflector Typically Specular Finish Typically Specular Finish 81 Blobs: PAR, MR, R 82 Blobs: PAR - Lamps 83 Lines 84 85 86 How Fluorescent Lamps Work 87 Fluorescent Lamp Design..the old way 88 Fluorescent Lamp Design Rapid start and starter switch fluorescent bulbs have two pins that slide against two contact points in an electrical circuit. 89 Spectral Power Distribution Curves Fluorescent Fluorescent Lamps produce a combined spectrum… a non-continuous or broad spectra with gaps from their phosphor, plus UV from the mercury discharge. 90 91 “Change a bulb and save the world!” 92 93 Fluorescent Systems Incandescent lamps are a simple thing. A bit of wire that gets very hot. It presents a very simple, resistive load to the electricity supply. Fluorescents on the other hand is much more complex. The electronics