A different theory for color vision B Demo Low Pressure Sodium Lamp 1 Color is

A different theory for color vision b demo low

This preview shows page 38 - 40 out of 106 pages.

A different theory for color vision B.Demo: Low Pressure Sodium Lamp 1.Color is totally mental!a.It’s a construction of our psychologyLow pressure sodium lamp emits only one wavelength of light2.a.Everything looks like the sepia filter! b.We turned off all other light and only allowed the yellow light to come through c.Only yellow items appeared yellow because the light reflected into our eye is yellow d.All other objects were some shade of gray C.Color and Light 1.Color signals help us classify and identify objects 2.Color facilitates perceptual organization of elements into objects Color vision may provide an evolutionary advantage in foraging for a.food 3.Electromagnetic Spectrum Visible light wavelengths between 400-700 nanometersa.Infrared spectrum in range of 1,000-100,000 nanometers (felt as heat)b.c.Ultraviolet below 200 nanometers (sunburns us) 4.How do we perceive color? a.Actually, there are no colors out there in the world. Color is not a physical property but a psychophysical property. Color perception is due to our sensory b.interpretation of information in the electromagnetic spectrum we interpret different wavelengths as different colors c.“There is no red in a 700nm light, just as there is no pain in the hooves of a kicking horse.”—Steven Shevell (2003) d.White light contains all the colors we see e.Rainbows raindrops split the white light (like a prism) and we see colors 5.Visible Spectrum a.Ultraviolet Vision i.Bees can see in ultraviolet, this is how they see calla lilies contrast: ii.The pistol of the flower is highlighted because that’s the important part for the bee (much sharper target) find more resources at oneclass.comfind more resources at oneclass.com
Background image
(Ultraviolet; Infrared ) b.Infrared Vision i.Snakes and vipers can detect infrared light (heat) 6.Light Interacts with Matter a.Chromatic colors or hues objects that preferentially reflect some wavelengths (selective reflectance) i.Reflectancethe light that bounces off an object into our eye b.Achromatic colorscontain no hues; white, black, gray tones (based on brightness) Whitec.reflects all wavelengths of light d.Gray- reflects some of all wavelengths e.Blackabsence of light being reflected off an object; absorbs all wavelengths of light f.Cyanreflect blue and green (S, M), absorbs red (L) g.Yellowabsorbs red and green (L, M); absorbs blue (S) h.Magentareflects blue and red (S, L); absorbs green (M) 7.Reflectance a.Spectral Reflectance Curvesobjects in the real world reflect light across the spectrum in different amounts (not usually single wavelengths)b.When white light shines on a colored object, some photons absorbed, and others reflected by the object’s surfacei.Color is so complicated and complex ii.This graph shows the various wavelengths that can be absorbed and reflectedD.Color Mixing: Lights vs Paints 1.Additive Color Mixture: a.Mixing lights of different wavelengths b.All wavelengths are available for the observer to see Adding wavelengths of light togetherc.d.
Background image
Image of page 40

You've reached the end of your free preview.

Want to read all 106 pages?

  • Spring '15
  • panut mulyono
  • Test, Homework, ganglion cell, receptive field

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture

  • Left Quote Icon

    Student Picture