GASB05H3 Chapter Notes - Chapter 5: Fuck, Color Vision
Chapter 5: The Perception of Colour
- Color is not a physical property of things in the world; creation of one’s mind
Basic Principles of Color Perception:
- Most of the light we see is reflected light
- The color of the surface depends on the mix of wavelengths and lights in the surroundings
- Pain = the interaction of a physical stimulus with a nervous system
-Three Steps to Color Perception:
1. Detection:
a. Wavelengths must be detected
b. Cones:
b.i. S-cones: sensitive to short
wavelengths (blue cones)
b.i.1. Rare!
b.ii. M-cones: sensitive to
medium wavelength (green
cones)
b.iii. L-cones: sensitive to long
wavelengths (red cones)
c. Spectral sensitivities overlap
2. Discrimination
a. Distinguish difference between wavelengths
b. Photoreceptor responds to light of a specific wavelength while the intensity
of the light is constant
c. Due to the properties of the photopigment in the photoreceptor cell:
c.i. 400 nm= small response in each cell of this type
c.ii. 500 nm= produces a greater response
c.iii. 550 nm= produce more light
c.iv. 600nm= produce less than maximal response
c.v. 650nm = minimal response
c.vi. 625 nm= moderate strength
d. Varying responses of this photoreceptor to different wavelength may
provide a basis for color vision
e. Lights of 450 and 625 nm each elicit the same
response from the photoreceptor whose responses
are shown here
e.i. Principle of univariance:
e.i.1. An infinite set of different wavelength-intensity
combinations can elicit the same response from one type of
photoreceptor
e.i.2. 1 photoreceptor cannot make color discriminations
based on wavelength
e.i.3. This shit explains the lack of color in dimly lit scenes
e.i.4. Only one type of photoreceptor, therefore all contain
the same type of sensitivity to wavelength
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Document Summary
Color is not a physical property of things in the world; creation of one"s mind. Most of the light we see is reflected light. The color of the surface depends on the mix of wavelengths and lights in the surroundings. Pain = the interaction of a physical stimulus with a nervous system. Three steps to color perception: detection: b. i. 1. Rare: wavelengths must be detected, cones: b. i. S-cones: sensitive to short wavelengths (blue cones) b. ii. M-cones: sensitive to medium wavelength (green cones) b. iii. L-cones: sensitive to long wavelengths (red cones) c. Spectral sensitivities overlap: discrimination, distinguish difference between wavelengths, photoreceptor responds to light of a specific wavelength while the intensity of the light is constant, due to the properties of the photopigment in the photoreceptor cell: c. i. 400 nm= small response in each cell of this type c. ii. 600nm= produce less than maximal response c. v. 650nm = minimal response c. vi.
