Allan Didier

Digitizing Color

How does the computer generate color from only 1’s and 0’s?  How is color digitized?

What Is Color?

  • Your eye detects certain frequencies of the electromagnetic spectrum
  • Different frequencies are seen as different colors.
  • Your eye only detects red, green, and blue colors. The other colors are made from a mix of these 3 colors.

What are the Primary Colors of Light?

  • Primary colors: RGB: red, green, and blue
  • Yellow = red + green
  • Cyan = green + blue
  • Magenta = red + blue
  • Use the Physics Simulation RGB light mixer to see the color interaction.

What are the Primary Colors of Pigment?

  • Primary colors for computer pigment: CMYK
  • C = Cyan (light blue)
  • M = Magenta (pinkish red)
  • Y = Yellow
  • K = Black (B = Blue)
  • Cyan + Magenta = Blue
  • Magenta + Yellow  = Red 
  • Cyan + Yellow = Green
  • Use the Physics Simulation CMY paint mixer to see he color interaction.

How is Color Digitized?

  • Light
    • Amount of each color is a binary number often in hex for humans.
    • Color = Red# + Green# + Blue#
    • 24 bit color (standard color scheme)
      • 3 colors (RGB)
      • 2 hex numbers per color (1 byte per color = 8 bits)
      • 3 colors * 8 bits = 24 bit color 
    • Red = ff 00 00
    • Green = 00 ff 00
    • Blue = 00 00 ff
    • Yellow = Red + Green = ff ff 00
    • Cyan = Green + Blue = 00 ff ff
    • Magenta = Red + Blue = ff 00 ff
    • What color number is white?
    • What color number is black
    • What color number is orange?
    • Use google docs color mixer to see this.
  • Pigment
    • Similar to above but using CMYK instead of RGB.
    • Cyan = ff 00 00 00

Digital Colors in Advertising

If you are doing graphic design, you run into digital colors all the time in software like Photoshop and Illustrator. The binary number for colors is also used for product advertisement all the time. For advertisers, making sure the color of their product matches from the the box, to television, to billboards, to the computer is very important. Some colors from advertisers have been etched in your minds. For example, can you picture in your mind the red color for Coca Cola? What about the yellow color in the McDonald’s arches? Do a quick Internet search for the following colors and find out what their binary color is? Check the number using Google Docs.

  1. Coca Cola’s Red
  2. McDonald’s Yellow
  3. Pepsi’s Red and Blue
  4. Diet Coke’s Silver
  5. M&Ms
  6. Skittles

A Figment of Your Imagination

Does everyone see color the same? Are colors absolute or relative? What colors are in the dress below? Blue and black, or white and gold?