colour perception Flashcards
3 reasons for colour
scene segmentation
comfouflage
perceptual organisation
what is colour?
visible light forms narrow band of freqs in EMS
within band, diff freqs have diff hues
ranging from red (long WL) to violet (short WL)
what gives objects colour?
diff objects absorb and reflect diff wavelengths
what are the 3 properties of light and their physiological attributes
wavelength= hue
intensity= brightness
spectral purity= saturation
what causes diff between red and blue
WL= hue
what causes diff between light and dark blue
intensity= brightness
what is the diff between red and pink
spectral purity= saturation
what does the trichromatic theory hypothesise
3 diff sorts of receptors that respond best to diff wavelengths of light
colour you see is determined by relative levels of activity in 3 sorts of receptors
what are the 3 receptors types in the trichromatic theory
blue sensitive cones, response to short WL (S-cones)
green sensitive cones, response to medium WL (m-cones)
red sensitive cones, response to long WL (L-cones)
what causes cones to respond to diff wavelengths
pigments in cones
what led to the opponent process theory
Hering noticed people picked red, green, blue (trichromatic theory) as pure colours but also yellow
also cones and fatigue werent understood so confused on how trichromacy could explain afterimages
what colours are opponent in terms of the opponant process theory
red-green
yellow-blue
balck-white
meaning eg red-green receptors signal either red or green
2 components of colour blindess
anopias- insensitive L,M or S wavelnegths of light (missing type of cone)
anomalies- misalignmnet of L or M trichromats
