The physics of color - Rey San Andrew Rimando


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The physics of color - Rey San Andrew Rimando

  1. 1. Rey San Andrew Rimando BSCivil Engineering
  2. 2. COLORS  Is the VISUAL PERCEPTUAL PROPERTY interacting in the eyes with the spectral sensitivities of the light receptors in different categories like RED, YELLOW, BLUE, GREEN, ORANGE, VIOLET.  Color categories and physical specifications of color are also associated with objects, materials, light sources, etc., based on their physical properties such as light absorption, reflection, or emission spectra.  Color derives from the Spectrum of Light (distribution of light powers versus wavelength)
  3. 3. Visible Light Spectrum; AnIntroduction Normally when we use the term "light," we are referring to a type of electromagnetic wave that stimulates the retina of our eyes. In this sense, we are referring to visible light, a small spectrum from the enormous range of frequencies of electromagnetic radiation. This visible light region consists of a spectrum of wavelengths that range from approximately 700 nanometers (abbreviated nm) to approximately 400 nm. Expressed in more familiar units, the range of wavelengths extends from 7 x 10-7 meter to 4 x 10-7 meter. This narrow band of visible light is affectionately known as ROYGBIV. Each individual wavelength within the spectrum of visible light wavelengths is representative of a particular color. That is, when light of that particular wavelength strikes the retina of our eye, we perceive that specific color sensation.
  4. 4. Color Vision in the Eye Three types of cones (color) One type of rod (B/W only)
  5. 5. Sir Isaac Newton - DISPERSION Showed that light shining through a prism will be separated into its different wavelengths and will thus show the various colors that visible light is comprised of. The separation of visible light into its different colors is known as dispersion. Each color is characteristic of a distinct wavelength; and different wavelengths of light waves will bend varying amounts upon passage through a prism. For these reasons, visible light is dispersed upon passage through a prism. Dispersion of visible light produces the colors red (R), orange (O), yellow (Y), green (G), blue (B), and violet (V). It is because of this that visible light is sometimes referred to as ROY G. BIV.(Incidentally, the indigo is not actually observedin the spectrum but is traditionally added to thelist so that there is a vowel in Roys last name.)
  6. 6. The red wavelengths of light are the longer wavelengths and the violetwavelengths of light are the shorter wavelengths. Between red and violet, thereis a continuous range or spectrum of wavelengths.
  7. 7. Wavelengths & PhotonsParticles of light, called photons, each have a wavelength. Red Photon Yellow Photon Green Photon Blue Photon Prism Spectrum
  8. 8. Additive Color Wheel There are RNo Photons Spectral of These Colors Colors M Y Red B G Yellow Green C Cyan Blue Magenta
  9. 9. Adding Color Lights Stream of red & green photons looks same as yellow photons (metamerism) Eye to Brain or Notice overlap of red, green, & blue is seen as WHITE light Theatrical lighting
  10. 10. Newton’s Color WheelPrism spectrum is astraight line, so whydid Isaac Newtondescribe color using acircular wheel?
  11. 11. Before we continue our discussion,Let me show you some tricks in Color Wheel
  12. 12. The Color Wheel The color wheel is a means of organizing the colors in the spectrum. The color wheel consists of 12 sections, each containing one hue.  A hue is a name of a color on the color wheel.  This lesson will discuss each of the colors, color harmonies and how they are created.
  13. 13. The Primary Color Triad  The primary colors yellow are, red, yellow and blue and are the purest and most intense of all the colors. The intensity of a color is the brightness or dullness of red blue a color. They form a triangle on the color wheel and are colors that cannot be mixed from any other colors. These are the only colors that can be found in nature.
  14. 14. The Secondary Color Triad The secondary colors are orange, green and violet and are duller orange green than the primaries because they have been mixed together. They form a triangle on the color wheel and are colors that are mixed from the primary colors. Primary + Primary = secondary Red + yellow=orange violet Blue + yellow= green Red + blue= violet
  15. 15. The Intermediate (Tertiary) Colors These colors are yellow-orange, yellow-green, blue-green, blue- Yellow violet, red-orange, red-violet Yellow orange green and are even duller than the secondary colors because the primary has been mixed with a secondary. Red Blue These 6 colors are formed by orange green mixing a primary and a secondary color. Primary + Secondary = Tertiary Red Blue yellow + orange=yellow-orange violet violet red + orange = red-orange red + violet =red-violet blue + violet = blue-violet blue + green =blue-green yellow + green = yellow-green
  16. 16. COLORWHEEL
  17. 17. Hue-Saturation DiagramEye is not a perfectoptical instrument.Color “wheel” isactually distortedcone shape.Rim is full saturation,center is white What color is present in the center? ANS= WHITE
  18. 18. Hue, Saturation, ValueColor wheel isnota single wheelbutstack of wheelsthat range invalue.
  19. 19. The Warm and Cool Color Scheme Warm colors range from: yellow yellow-orange orange red-orange red red-violet Cool colors range from: yellow-green green blue-green blue blue violet violet
  20. 20. Grayscale A value scale is a scale of grays running from black to white.
  21. 21. Spectral Reflectance Curves When white light shines on a colored object, some photons absorbed, others reflected by the object’s surface.
  22. 22. Neutral ColorsNeutral Colors are those colorsnot found on the color wheelbut are mixed by other colorson the color wheel. White Brown Gray Black
  23. 23. MONOCHROMATIC Having only one color. Here I used all shades of red to create the design
  24. 24. ANALOGOUS Uses Colors that are next one another on the Color Wheel
  25. 25. COMPLEMENTARY Consists of colors that are opposite of one another on the color wheel.
  26. 26. TRIADConsists of a color and the colors to the left and right of its complement
  27. 27. Let’s do an example..Let’s Try!
  28. 28. Negative After-imageStare, unfocused, at the red cross for 10 seconds then look at white wall
  29. 29. Negative After-image Cyan
  30. 30. Negative After-image Stare, unfocused, at the flag for 10 seconds then look at white wall
  31. 31. Negative After-image Cyan Magenta Yellow
  32. 32. Simultaneous Contrast Does the gray bar look slightly bluish? Are the two gray bars the same shade of gray?Yes, the presence of a nearby color affects perception of bothhue and value, shifting both towards complement