Additive vs' Subtractive

1
Color Mixing

• Additive vs. Subtractive

There are two different ways to mix colors.
2
Color Mixing

• Additive vs. Subtractive

What do you get if you use a prism to combine all
wavelengths of light?
3
Color Mixing

• Additive vs. Subtractive

What do you get if you use a prism to combine all
wavelengths of light?
White
4
Color Mixing

• Additive vs. Subtractive

What do you get if you mix a bunch of paint?
5
Color Mixing

• Additive vs. Subtractive

What do you get if you mix a bunch of paint?
Black
6
Color Mixing

• Additive vs. Subtractive

WHY?
7
Color Mixing

• Additive mixing is most intuitive

ADD wavelengths redgreen yellow redblue
magenta bluegreen cyan redgreenbluewhite
8
Color Mixing

• What color can only exist as a metamer (an
  additive mixture of wavelengths)? In other
  words, what color cannot be made with a single
  wavelength?

9
Color Mixing

• What color can only exist as a metamer (an
  additive mixture of wavelengths)? In other words,
  what color cannot be made with a single
  wavelength?

Magenta
Think about why!
10
Color Mixing

• Subtractive mixing is much less intuitive (but
  much more common)
• Subtractive mixing happens when we mix pigments
  (paint) together
• Different pigments subtract different
  wavelengths
• red subtracts all but red, blue all but blue,
  green subtracts blue and red, etc

11
Color Mixing

• Example blue yellow green

Technically its called cyan
12
Color Mixing

• The result of a mixture depends on what
  wavelengths dont get absorbed by the two pigments

Amount of filtering
green
yellow
red
blue
wavelength
13
Color Mixing

• Both yellow and blue pigments reflect a bit of
  green

Amount of filtering
green
yellow
red
blue
wavelength
14
Color Mixing

• Subtractive mixing is commonly used in color
  printers

15
Color is illusory

• Everything youve learned so far is wrong.

16
Color is illusory

• Everything youve learned so far is wrong.
• Well, not really wrong, just far from complete.

17
Color is illusory

• Everything youve learned so far is wrong.
• Well, not really wrong, just far from complete.
• You will read in the article by Land that the
  color of a surface depends as much on the colors
  of the surrounding surfaces as it does on the
  wavelength of light it reflects.

18
NEXT TIME

• Read article by Land