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A L L A B O U T C O L O R

A L L A B O U T C O L O R. CGS3066. Is color. Inherent in objects– do objects HAVE color? or Something created by the mind of the beholder when he/she perceives light?. Here’s where light fits in. And yet the human eye can distinguish as many as.

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A L L A B O U T C O L O R

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  1. ALLABOUTCOLOR CGS3066

  2. Is color Inherent in objects– do objects HAVE color? or Something created by the mind of the beholder when he/she perceives light?

  3. Here’s where light fits in

  4. And yet the human eye can distinguish as many as • 100, 000 • 1,000,000 • 10,000,000 ???? colors

  5. How We See Three distinct eye layers • Sclera: Outer layer, includes cornea • Choroid: Middle layer, has blood supply, iris • Retina: Image surface, contains photoreceptors

  6. Picture of Retina

  7. Rods and Cones Cover Retina Cones Rods Retina schematic

  8. Rods versus Cones • Many more Rods- all same kind -- 120 million (night vision) • 7 million cones (day vision) • 3 kinds of cones, each sensitive at different range of wavelength • Humans have “Trichromatic” vision • why colors requires 3 numbers to specify

  9. Sensitivity of Cones re Wavelength “Short” “Medium” “Long” Few of these Many of these

  10. We have 3 kinds of cones but many Animals have only two- ie are dichromats Here is how the world looks to them What would a tetrachromat see?

  11. Rods and cones in humans summed up If we had only _______, we’d see only in black and white. It’s the ________ that give us color vision.

  12. What you need to remember about human color perception Where vision fits into the spectrum Roughly how many colors humans can perceive How the retina works: cones and rods Difference between human and animal vision (Trichromatic vs dichromatic)

  13. 2 Basic Approaches to Color Subtractive systems RYB and CMYK (pigment) all colors make black Additive system RGB (light) all colors make white

  14. Subtractive Color: for pigment Paint: RYB redyellowblue Primary colors: red yellow blue Secondary colors: 2 primaries Tertiary colors: 1 secondary 1 primary Printing: CMYK cyanmagentayellow black

  15. But Red, yellow, and blue aren’t technically primary colors at all, because • they can’t reproduce as many ___________ and - they can’t get as close to true _______ as cyan magenta and yellow can.

  16. Additive Color: For Light RED GREENBLUE

  17. light-generated color   for graphics/backgrounds intended for screen display Red + blue = magenta blue + green=cyan green + red = yellow mix everything you get white

  18. RGB in HTML 3 numbers 1-255 designates the amount of RED, GREEN, or BLUE Black- 100% of all three White- 0% of all three

  19. Hexadecimal Color Here is an example: 255 RED 255 GREEN 0 BLUE translated into hexadecimal FFFF00

  20. Huh? Hex means to the base 16 instead of 10 The 16 positions :0123456789ABCDEF Each RGB component is a 2 position hex # The smallest would be 00, the biggest FF

  21. Furthermore… The absence of color is black – (000000) so the closer to 00 a designation for RGB is, the darker it is and the closer to FF the brighter it is The saturation of all colors is white-- All Fs ( FFFFFF)

  22. RGB CMYK To reproduce a RGB image in ink on paper, it must be converted to "CMYK" CMYK and RGB not perfectly compatible - deep blues and rich reds on screens won’t print using "SWOP CMYK" inks (SWOP: standard web offset press)) - pure cyan in CMYK can’t be duplicated on a computer screen

  23. So….CMYK is anticipating print (cyanmagentayellow black) for computer graphics intended for paper subtracts Cyan S red yellow S blue magenta S green. mix everything you get black

  24. Web-Safe Color - any color can be specified in hex but different browsers don’t define them identically - colors using only 00,33,66,99,CC,FF are common across browsers • SO, there are only 216 web-safe colors (6 cubed) versus 16,777,216 theoretical possibilities (256 cubed)

  25. A color poster for the web Here are web colors derived from a color wheel: http://www.visibone.com/colorlab Don’t use too many Good to choose colors from the middle- outside ones are too bright

  26. Some Approaches to Coordinating Colors Monochromatic One color plus hues, tints, shades To increase intensity, add white http://www.carbonplaces.com/

  27. Some Approaches to Coordinating Colors Complementary: - Across from each other on the color wheel - These can clash • Used side by side can cause problems for the eye because are very different wavelengths

  28. Some Approaches to Coordinating Colors Triadic Colors chosen by drawing an equilateral triangle inside a color wheel

  29. Sources of Eye Strain Too little contrast between text and background– contrast should be 80% Complementary colors side by side cause shadows and vibrations

  30. The Effects of Color Certain colors trigger a physical reaction red raises blood pressure blue lowers it

  31. Some More Effects Colors evoke styles: Can date: eg Avocado- 60s and 70s Can pigeonhole: blue and green- preppy

  32. Implications of Color Choice Cultural: Flag colors, for example Different symbolic messages in west white = purity in east can = death

  33. Test yourself on western color symbolism http://desktoppub.about.com/library/ quizzes/blcolormatching.htm

  34. 2 General Color-Group Effects Cool Colors calm (Blue, Green & White) Warm Colors excite (Red, Yellow, Orange & Black)

  35. Color Blindness about 8 of every 100 men 1 of every 200 women doesn’t mean can’t see color just can’t tell red from green

  36. Are you color blind? http://colorvisiontesting.com

  37. how color blind people see http://www.vischeck.com/examples/ This site will let you check your site for colorblindness problems

  38. What Colors are Safe for All? http://more.btexact.com/people/rigdence/colours/

  39. Does Color Matter? • Research reveals all human beings make a subconscious judgment about an item within 90 seconds of initial viewing and that between 62% and 90% of that assessment is based on color alone.

  40. Does color matter? • Close to 40% of American consumers report they would change car makes if they couldn’t get the color of their choice • Source: Institute for Color Research

  41. Some design advice • Limit your color palette to no more than three colors to reduce visual clutter. • Use colors appropriate to the theme of your web site. • Use colors found in key photos or graphics on your web page for added harmony. • Avoid harsh colors. Desaturate colors to approximate colors found in nature and textiles.

  42. A Terrific Site for Color Info • http://www.colormatters.com/entercolormatters.html

  43. One more Source for Color Choice http://www.2createawebsite.com/build/hex-colors.html

  44. Vision is not simple: Some Illusions

  45. Is the Green Dot in Front or Back of Cube?

  46. Which Avocado Has the Pit?

  47. Is the Green Dot in Front or Back of Cube?

  48. Hidden Bird Illusion http://zeus.rutgers.edu/~feher/bird/example1.html

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