Lec 15 Flashcards
colors in ADDITIVE MIXING & what color u start with & what if u mix ALL colors together
Light: PRIMARY COLOR-->red, green, blue
start w/ BLACK (ABSENCE OF LIGHT)
mix all together -->WHITE light
R
Yellow Magenta
G Cyan Bcolors in SUBTRACTIVE MIXING & what color u start with
MEDIA: printer ink –>cyan, magenta, yellow
start w/ WHITE (all light is reflected)
mix all together –>BLACK (no light is being reflected)
Y
red green
M blue C
why is a cone response UNIVARIANT?
are cones COLORBLIND?
ex: green cone–>what type of response does it have when u shine white & blue light on it?
what is this response of the cone “relative” to?
yes! they're color bind. univariant-->only response to # photons it absorbs, but absorbs a broad spectrum. more sensitive to certain wavelengths at ~500nm SPECTRAL SENSITIVITY). green cone (M): responds to moderate white light=blue light the SAME! "relative" to 1) wavelength 2) intensity (certain # of lumens emitted from source)
another name for CIE diagram?
what are the #’s around the outside?
why does the bottom of the diagram have no numbers?
CHROMATICITY DIAGRAM
#’s –>wavelengths of light you could see
no numbers because its the color PURPLE& all its shades
is purple spectral color?
nope! mix of red+blue
“non spectral purples” -what it says at the bottom of CIE diagram
what is the TRICHROMATIC THEORY of color vision?
3 classes of cone receptors each subserving different color spectrums (wavelengths of light): SHORT, MEDIUM, LONG WAVELENGTH CONES
18th century
mix any 2 of these color create all colors of visible spectrum
what test was used to determine how cones worked to process light they used? (i.e. Trichromatic theory)
microspectrophotometry
1980’s
Output-Input=light absorbed
what do typical OS of cones look like in fovea?
longer–>more surface area –>more sensitive–>better VA possibly cuz of this
lec 15 slide 7
what does this graph tell us & about the study done? what are the wavelengths associated?
microspectrophotometry **related wavelength to specific cone blue rods green red:
why does ISHIHARA test work? what colors does it mainly test for?
TRICHROMACY of vision
red & green (not so much blue)
tests whether patients red wavelength cones have been shifted more to green
what color are L & S cones stimulated more by compared to M cones?
purple hues –>L looks like its stimulated more than S AND both definitely stimulated a lot more than M
see graph: lec 15 slide 9
bottom pic: **L & S stimulated more EQUAL response-more of a true purple response
if purple stimulates L & S cones more does violet also stimulate L & S cones more than M as well?
No! it does not stimulate the same cones, but it is hard to distinguish violet form purple
which PR are most sensitive to short wavelengths of light?
ANS: red, green, blue, rods
rods! **10^3 more sensitive than cones
lec 4: ERG spectral sensitivity
rods & cones sensitivity similar around longer wavelengths (650nm-750nm), BUT before rods graph much higher –>more sensitive
does trichromatic theory explain how color is processed?
nope! it only explains how…
CONES ABSORB LIGHT
defines way the RETINA allow VISUAL SYSTEM to DETEXT COLOR (3 cones detecting)
what the opponent process theory?
who invented it?
what did that guy “observe”?
what colors was he talking about?
*“process” -key word in theory name
accounts for MECHANISM that RECEIVES & PROCESSES information from our CONES-explains how the 3 cones in the TRICHROMATIC THEORY make color
ewald hering (1892)-certain pairs of colors no one ever sees together
yellow-blue: crayons (green) & light (white)
red-green: crayons (ugly brown) & light (yellow)
