Color Physics @Hampshire, Day 11

March 12, 2017 /

Day 11 was more or less a rehash of the second half of Day 10, but in more depth and with more contact points with the visual arts. 

The topics covered were:

  • Infrared and ultraviolet photography.
  • Metamers.
  • Missing complementary pairs of spectral colors.
  • Three types of additive color mixing and its applications:
    • Direct addition of lights (TV monitors and projections on white surfaces in stage design).
    • Partitive mixing and pointillism in painting (Seurat, Signac, and van Gogh).

      A self portrait of van Gogh's as an example of the pointillist painting technique which relies on the principle of additive color mixing.
      A self portrait of van Gogh’s as an example of the pointillist painting technique which relies on the principle of additive color mixing.
    • Mixing light “in time” with Newton’s disks, which students made for a homework assignment a few weeks ago.

Finally, we formally introduced subtractive mixing with filters and the transmittance graphs. Students then used diffraction gratings to break up the light from a tungsten lamp, observed which colors were absorbed by various filters, and sketched the transmittance graphs for those filters.

Student observing the color spectrum after the light has passed through a filter.
A student observing the color spectrum generated by a diffraction grating after the light has passed through a filter.

Other interesting resources: