PSY 162 Lecture Notes - Color Photography, Pointillism
TV & Movies
● Is pointillism - with super fine detail
● The TV (and color printing, color photography…) use only 3 colors
○ Red,green & blue
○ This is all we need to mix
○ More than this would influence resolution
■ Reds need to be longer than our cones
To Create Images
● To reproduce images, 3 seperate reproductions are made
○ Through red, green and blue filters
○ Luminance is acquired in each of the color specific channels
○ Then three imagined are combination
○ The red of her coal would reflect red luminance - but not blue or green
○ The white of her hat would activate all equally
What else…
● We do not see only red, blue & green
○ Our visual system blends colors in 3 ways
■ Chromatically
■ Spatially
■ Temporally
Chromatically
● We do not only see red, green & blue-
○ We see all the colors in between
○ The visual system blend colors
○ Perception of color depends on the ratio of activation of the 3 cone types
Spatially & Temporally…
● Spatially
○ The pixels are too small to be seen by the photoreceptors
○ Photographs & images also use small dots that blend
● Temporally
○ The pattern of images flicker across the screen at a rate of `30 images/second
Broadcasting and Color
● In TV at the beginning and end of the process colors are coded as red, green & blue
○ Each individual image is the result of a series of sequentially illuminated
miniscule dots
● In the intermediate stage (broadcasting & videotapes) colors ar coded more like hor our
visual system handles color
Broadcasting & the VS
● In the VS
○ We first record an image as 3-cone signal
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