Lecture 23 Flashcards
Human visual wavelength
400 nm for violet to 700 nm for red.
Most humans sense color with _____ of cone
3 kinds
What are the 3 types of cone and how common are they?
~63% of the cones are red, 31% are green, and just 6% are blue.
trichromats
Animals that sense colour with 3 types of cones
How can we perceive any colour?
by mixing 3 wavelengths
Spectral colors
are those that can be evoked by light of a single wavelength. They are the rainbow colors, from violet through blue, green, yellow and orange to red.
Extra-spectral colors
such as purple or white are evoked only by a mix of wavelengths, e.g. we see purple when 2 or more wavelengths affect red and blue cones more than green cones
How many cones do most mammals have?
2
Daltonism
a name for red-green color blindness, where people have trouble distinguishing those colors
What signals are produced when cone signals are combined
Ganglion cell color signals
What are R+G cells/ the yellow channel?
ganglion cells that are excited by red light and by green light
How is yellow made with light?
by combining red and green
What are R-G cells?
ganglion cells that are excited by red and inhibited by green
What are B-(R+G)/ (B-R-G) cells?
ganglion cells that are excited by blue light and inhibited by red and green
What was the first human trait to be linked to a chromosome?
Color blindness
