1) Good lighting design is important for creating the right mood and allowing people to perform activities in homes. Lighting must be tailored to the different spaces and uses within a home. 2) Light is a form of electromagnetic radiation that makes vision possible. Key factors that affect light include its wavelength, sources like incandescence and luminescence, and how it behaves through reflection, refraction, and interactions with materials. 3) Proper lighting design considers factors like illuminance, luminance, lighting types like general, accent, decorative, and task lighting, and how light impacts vision and psychology within a space. A variety of artificial light sources exist that must be selected appropriately.

1. Light and Lighting

2. Introduction Good lighting can make or break a home in the same way that furnishings and interior decoration set a style, yet too often lighting is treated as an afterthought. Designing light require the architect to start with the space to light and most importantly will look at what space is FOR. Designers must treat space as a dynamic entity because homes are not static showpieces, people live in them and lighting design must account the different activities in each spaces. Every human activity needs different lighting state that gives the right levels of light for visual task on appropriate mood. Finally, the quality of lighting design must evoke the emotional feeling of the space.

3. Light Energy producing brightness: the energy producing a sensation of brightness that makes seeing possible Is visually perceived radiant energy on the electromagnetic spectrum in the range visible to the human eye.

4. Visible light comprises only a very small part of the energy spectrum yet makes it possible for people to see. Light and color affects human sight. Color is determined by wave length (370 nanometers to 800 nanometers)1 nanometer = 1billionth of a meter Longest wavelength has lowest frequency and shortest wavelength has highest frequency Fundamental Laws of Light

5. Electromagnetic Spectrum

6. Sources of Light Incandescence In an incandescent light source, hot atoms collide with one another. These collisions transfer energy to some electrons, boosting them into higher energy levels. As the electrons release this energy, they emit photons. Some collisions are weak and some are strong, so the electrons are excited to different energy levels and photons of different energies are emitted. Candle light is incandescent and results from the excited atoms of soot in the hot flame. Light from an incandescent light bulb comes from excited atoms in a thin wire called a filament that is heated by passing an electric current through it.

7. Sources of Light Luminescence A luminescent light source absorbs energy in some form other than heat, and is therefore usually cooler than an incandescent source. The color of a luminescent source is not related to its temperature. A fluorescent light is a type of luminescent source that makes use of chemical compounds called phosphors..

8. Sources of Light Laser A laser is a special kind of light source that produces very regular waves that permit the light to be very tightly focused. Laser is actually an acronym for Light Amplification by Stimulated Emission of Radiation. Each radiating charge in a non laser light source produces a light wave that may be a little different from the waves produced by the other charges. Laser sources have atoms whose electrons radiate all in step, or synchronously. As a result, the electrons produce light that is polarized, monochromatic, and coherent, which means that its waves remain in step, with their peaks and troughs coinciding, over long distances.

9. Behavior of Light Light behavior can be divided into two categories: how light interacts with matter and how light travels, or propagates through space or through transparent materials. The propagation of light has much in common with the propagation of other kinds of waves, including sound waves and water waves.

10. is the bending of light when it passes from one kind of material into another. Because light travels at a different speed in different materials, it must change speeds at the boundary between two materials. If a beam of light hits this boundary at an angle, then light on the side of the beam that hits first will be forced to slow down or speed up before light on the other side hits the new material. This makes the beam bend, or refract, at the boundary. Refraction

11. Reflection Reflection also occurs when light hits the boundary between two materials. Some of the light hitting the boundary will be reflected into the first material. If light strikes the boundary at an angle, the light is reflected at the same angle. Light that is reflected from a flat boundary, such as the boundary between air and a smooth lake, will form a mirror image. Light reflected from a curved surface may be focused into a point, a line, or onto an area, depending on the curvature of the surface.

12. Types of Reflection Specular – Directed from a smooth polished surface Diffused – A scattered reflection of light from an irregular surface or an erratic dispersion through a translucent material.

13. Reflectance – The ratio of the radiation reflected by a surface to the total incident on the surface Absorptance – The ratio of the radiation absorbed by a surface to the total incident on the surface Transmittance – The ratio of the radiation transmitted through and emerging from a body to the total incident on it, equivalent to 1 minus the absorption

14. Materials in relation to Light Opaque – Impenetrable to light Translucent – Transmitting and diffusing light so that bodies on the opposite side are not clearly visible Transparent – Capable of transmitting light so that bodies situated beyond or behind can be distinctly seen.

15. Lighting The science, theory, or method of providing illumination through the use electric lamps

16. Lighting Fundamentals Candlepower – The Intensity of light from a source in a certain direction, and measured in candelas. Coefficient of Utilization – The ratio of illuminance to the lumens radiated from the light source. Efficacy – The ratio of the approximate initial lumens produced by a light source divided by the necessary power to produce them.

17. Lighting Fundamentals Footcandle – A unit of illuminance measurement; the number of lumens that are incident on each square foot of work surface. 1fc = 10.76 lux Illuminance – The light falling on a surface, measured in footcandles or lux. Lumen – A measure of total light producing output of a source; the quantity of visible light emitted.

18. Lighting Fundamentals Luminaire – An assembly used to house one or more light sources. Also called lighting fixture. Luminance – The emitted or reflected light from a surface in a particular direction, measured in candelas per square meter. Lux – A unit of measurement used to gauge the illuminance falling on a surface; the number of lumens incident on each square meter

19. Luminance and Illuminance

20. Categories of Luminaires Direct: 90 – 100% downward Semi direct: 60 – 90% downward General diffuse: 40 – 60% both downward and upward Direct – indirect: little light is emitted in the horizontal plane Semi – indirect: providing 60 – 90% of its output upward Indirect: providing 90-100% of its luminous output upward.

21. Classification of Luminaires Recessed Ceiling Mounted Track Mounted Wall mounted Suspended Architectural Portable Pole Mounted Bollard Outdoor

22. Lighting and Vision Factors that affect visual performance independent of lighting Contrast: refers to the luminance difference between the critical detail of a task and its immediate background Size: refers to the size of the visual task Time: refers to the time a visual task is presented.

23. Factors that affect visual performance dependent on lighting Task Luminance Reflectance of a surface Veiling Reflections: reflections that create a luminous veil over a visual task Glare: an annoying or painful sensation caused by the non-uniformityof lighting Lighting and Vision (cont.)

24. Veiling Reflection Glare

25. The following means can reduce discomfort glare Decrease the luminance of the offending source of light Reducing the area or size of the offending source Increasing the luminance of surfaces surrounding the offending source

26. Lighting and Psychology Research has resulted in some approaches to lighting a space that tend to reinforce some subjective impressions. Visual Clarity: reinforced by bright, uniform lighting combined with high brightness of the walls Spaciousness: reinforced by uniform wall lighting Relaxation: reinforced by non-uniform lighting and lower ceiling brightness Privacy/Intimacy: reinforced by non-uniform lighting (low levels around the occupants, higher levels further away) Pleasantness/preference: reinforced by non-uniform lighting with high wall brightness

27. Artificial Light Sources Incandescent Lamps Fluorescent Lamps High – Intensity Discharge Lamps Mercury Lamps Metal Halide Lamps High Pressure Sodium Lamps Low Pressure Sodium Lamps Electrodeless Lamps Compact arc xenon and Mercury Lamps Electroluminescent Lamps Light Emitting Diodes Carbon arc Lamps Gaslights

28. Lighting Calculations Illuminance Inverse Square Cosine Law E =(I cosx)/D2 Where: I is the Luminous Intensity in Candelas D is the distance between the source and the point and the angle x between the normal or perpendicular to surface A and the direction along the distance D Luminance L = rE/ Where: r is the reflectance, and E is the illuminance in lux

29. Types of Lighting General Lighting

30. Types of Lighting Accent Lighting

31. Types of Lighting Decorative Lighting

32. Types of Lighting Task Lighting

33. Types of Lighting Kinetic Lighting