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test 1

  1. 1. C O L O R <ul><ul><li>In Multimedia Applications … </li></ul></ul>
  2. 2. The Science of Light <ul><li>Light is electromagnetic energy </li></ul><ul><li>Produced by atoms </li></ul><ul><li>Exists in a range of frequencies </li></ul><ul><li>The visible range is COLOR </li></ul>
  3. 3. What is Color? <ul><li>The visible range of light </li></ul><ul><li>A continuum: </li></ul><ul><ul><li>Red </li></ul></ul><ul><ul><li>Orange </li></ul></ul><ul><ul><li>Yellow </li></ul></ul><ul><ul><li>Green </li></ul></ul><ul><ul><li>Blue </li></ul></ul><ul><ul><li>Violet </li></ul></ul><ul><li>Black is absence of color </li></ul><ul><li>White is presence of all colors </li></ul>
  4. 4. Human Color Perception <ul><li>Light rays stimulate nerves </li></ul><ul><li>Receptors are sensitive to red, green, and blue light </li></ul><ul><li>Can interpret thousands of combinations </li></ul>
  5. 5. Screen Colors <ul><li>An additive process of combining colored light made of 3 primary colors: </li></ul><ul><ul><li>Red </li></ul></ul><ul><ul><li>Green </li></ul></ul><ul><ul><li>Blue </li></ul></ul><ul><li>Each pixel displays a single color with a specific RGB number </li></ul>
  6. 6. Print Colors <ul><li>A subtractive process of combining colored inks that reflect light: </li></ul><ul><li>Each printed dot is made up of 3 primary colors: </li></ul><ul><ul><li>Cyan </li></ul></ul><ul><ul><li>Magenta </li></ul></ul><ul><ul><li>Yellow </li></ul></ul>
  7. 7. Color Models <ul><li>There are several models to describe colors with a computer: </li></ul><ul><ul><li>RGB </li></ul></ul><ul><ul><li>CMYK </li></ul></ul><ul><ul><li>HSB/HSL </li></ul></ul><ul><ul><li>Others </li></ul></ul>
  8. 8. RGB <ul><li>Set red, green and blue to values in the range of 0 to 255 </li></ul><ul><li>All colors are expressed as a combination of those 3 values </li></ul>
  9. 9. CMYK <ul><li>Used for print media </li></ul><ul><li>Colors are mixed with different values of: </li></ul><ul><ul><li>Cyan </li></ul></ul><ul><ul><li>Magenta </li></ul></ul><ul><ul><li>Yellow </li></ul></ul><ul><ul><li>Black </li></ul></ul>
  10. 10. HSB/HSL <ul><li>Hue is specified as an angle from 0 to 360 degrees </li></ul><ul><li>Saturation and Brightness/Lightness are specified as percentages </li></ul><ul><ul><li>O% saturation is without color </li></ul></ul><ul><ul><li>50% lightness/brightness is a pure color (no black or white) </li></ul></ul>
  11. 11. Other Models <ul><li>CIE describes color in terms of frequency, saturation, and illuminance </li></ul><ul><li>YIQ/YUC are based on luminance and chrominance </li></ul><ul><li>YCC represents digital information converted from photographic images </li></ul>
  12. 12. Monitors <ul><li>Color resolution will vary depending on: </li></ul><ul><ul><li>Screen resolution </li></ul></ul><ul><ul><ul><li>800x600 </li></ul></ul></ul><ul><ul><ul><li>1024x768 </li></ul></ul></ul><ul><ul><li>Hardware color depth </li></ul></ul><ul><ul><ul><li>16 bit </li></ul></ul></ul><ul><ul><ul><li>24 bit </li></ul></ul></ul><ul><ul><ul><li>32 bit </li></ul></ul></ul>
  13. 13. Palettes <ul><li>Tables that define the color of a pixel: </li></ul><ul><ul><li>1 bit = 2 colors </li></ul></ul><ul><ul><li>4 bits = 16 colors </li></ul></ul><ul><ul><li>8 bits = 256 colors </li></ul></ul><ul><ul><li>16 bits = 65k colors </li></ul></ul><ul><ul><li>24 bits = 16m colors </li></ul></ul>
  14. 14. Dithering <ul><li>An image can contain many colors </li></ul><ul><li>Monitors are limited in the number of colors displayed at once </li></ul><ul><li>Image colors must be mapped to a palette </li></ul>
  15. 15. C O L O R … adds a new dimension
  16. 16. RGB Combinations Click to return Black White X X X Cyan X X Magenta X X Yellow X X Blue X Green X Red X Blue Green Red
  17. 17. RGB Values Click to return White (255,255,255) Black (0,0,0) Cyan (0,255,255) Magenta (255,0,255) Yellow (255,255,0) Blue (0,0,255) Green (0,255,0) Red (255,0,0)
  18. 18. Hue Values Click to return 300 degrees Magenta 240 degrees Blue 180 degrees Cyan 120 degrees Green 60 degrees Yellow 0 degrees Red
  19. 19. Combining Colors Click to return