C O L O R and Perception: Newton vs Goethe

Interactively Explore Color Mixing Applets Here: Very Good Resource

Executive Summary:

Newton's theory of color involves color addition which leads to the idea that Red , Green and Blue are the primary colors.

Goethe's theory of color involves color subtraction which leads to the idea that Magenta , Cyan, and Yellow are the primary colors.

These concepts were demonstrated in class. Note today they are very relevant to the production of media. Color print uses largely color subtraction sources as the paper is illuminated by ambient light.

Sources of color with their own illumination (e.g. the computer monitor upon which you are reading this) operate via color additions and use RGB pixels.

While Newton is most famous for developing mechanics, gravitational theory and calculus, in his spare time he also invented optics. Physicists like Newton only occur once every 1000 years.

Newton used a prism to show that the white light of the sun was actually made of component colors

A prism is known as a dispersive element. Incoming light interacts with the atoms in the prism which results in the light being diffracted into component colors. Objects in nature appear to have color based on the relative reflectance and absorption of these component colors. For instance, a leaf strongly absorbs red and blue light but reflects green light and hence appears green

Make your own colors here

How the Eye works to perceive light and color

Some paintings based on Goethe's Theory

Color Addition (RGB) and Color Subtraction (CMY) or complimentary:

• Cyan overprinting yellow produces green.
  • Cyan + Yellow = Green
• Cyan overprinting magenta produces blue.
  • Cyan + Magenta = Blue
• Magenta overprinting yellow produces red.
  • Magenta + Yellow = Red

  The subtractive color theory is based on the principle that the secondary colors of light can selectively subtract the components of white light to produce other colors and when all three components are subtracted the result is black.

  So we have:

  Additive color

  Subtractive color

  One can define primary colors for the print medium like this:

  

  Second colors as such:

  

  Tertiary Colors further:

  

  So for high contrast one uses complenetary colors, those on the opposite side of each other on the color wheel:

  

  And just so you can better understand the digital age, Adobe Photoshop and all of that - here is a brief guide to common color terms and their meanings:

  Hue:

  the "name" of a color, defined by the wavelength of light shown

  

  Saturation:

  the relative intensity, or purity, of a color, defined by how many different wavelengths are present

  

  Tint:

  decreasing the intensity of a color by making it lighter

  Tone:

  decreasing the intensity of a color by adding it's complementary color wavelength

  Shade:

  decreasing the intensity of a color by making it darker

  Value:

  the relative darkness or lightness of a color (as if it were photographed with black and white film)