Suppose you are viewing a coffee mug with a reflectance shown in Graph B while it is being illuminated by a light shown in Graph A. The wavelengths present in the light reflected from the mug will be the wavelengths where the two graphs overlap (i.e., percentage reflectance from Graph B multiplied by intensity from Graph A at each wavelength). This is shown in Graph C.
Graph A Graph B Graph C
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If we had no color constancy, what color would the mug appear to be in this situation? In a sentence or two, explain why. (4 points)
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After color constancy adjusts our perception, what color would the mug appear to be? In a sentence or two, explain why. (4 points)
Based on the light reflected from the mug, the wavelengths present in the illuminating light, and the reflectance properties of the mug, briefly explain what the brain must do in order to make this correction to our perception of the mug's color. (4 points)
Spectral power distribution of illuminating light
Spectral power distribution
Reflectance of a coffee mug
Intensity of light reflected from the mug
100 Reflectance (%)
75
50
25
Intensity
3 - 0
700
400
0
400
0
400
550
700
550
550
700
Wavelength (nm)
Wavelength (nm)
Wavelength (nm)