Lecture 10 Study Guide

Question 1

subtractive color mixing

Answer 1

This is selective transmission, but the new liquid should
transmit even less than the two individual liquids. The
pigments of each color absorb (subtract out) certain frequencies of light. So together, they absorb even more colors than they do individually.

– Mixing paints with different pigments.

– Additional pigments reflect fewer wavelengths, changing the selective reflectance.

– Mixing blue and yellow leads to green, because each pigment
alone would reflect green.

Question 2

additive color mixing

Answer 2

Mixing lights of different, specific wavelengths.

– All contributed wavelengths are available for the observer to see – direct combination of wavelengths

– Superimposing blue and yellow lights leads to white.

Question 3

how color matching experiments were used to support trichromatic
color theory.

Answer 3

Observers adjusted intensities of three wavelengths in a comparison field to match a test field of one
wavelength.

– Normal observers need three wavelengths of light to make the matches.

– Color matches based on different physical stimuli are called metamers.

– Strong evidence for the trichromatic theory and allows you to build a
model and look for physiological (implementational) causes.

Question 4

the different absorption spectra of cone pigments and how different
combinations of activity can produce metamers

Answer 4

Color matching experiments show that colors that are perceptually
similar (metamers) can be caused by different physical wavelengths.

Question 5

what afterimages are and how they are used to support the opponent-process theory of color vision

Answer 5

characteristic pairings: red after green adaptation, and blue after yellow adaptation.