PSY 162 Lecture Notes - Lecture 12: Glossary Of Computer Graphics, Fluorescent Lamp, Opponent Process
How kinds of light influence our perception
● We have natural daylight
○ But also
○ Tungsten light - with more red waves
■ Things appear more orange/red
○ Fluorescent light - about the same as daylight
○ Sodium vapor lights - very yellow * makes it hard to see color at all
Colored Shadows
● We see colored shadows when an object is being lit by several color illuminations
● We usually don’t notice because most changes are gradual
● Shadows are an abrupt a change
○ So they are notice by the what system
○ (red light + green light = white light)
Sodium Vapor Lights
● Everything looks yellow!
○ It is actually quite hard to distinguish color under SV lights
○ Emit a monochromatic light of 589 nm
■ We subtract the difference
■ After adaptation the yellow cells fatigue
■ We are better able to make comparisons between surfaces
Umm, cool- but so what?
● Well - IF we didn’t have the center surround organization
○ That allow us to compare the different sources of light
○ The same objects would look different depending on their light source
○ The opponent process organization allows us to perceive objects similarly in
different contexts
Color Mixing and Color Resolution (Back to the What)
The subdivisions of the What
● Form & Color
● Color (color cells are larger) operates at surprisingly low resolution (Type 2 cells, Type 1
deals with form)
○ Cells in the color system have larger receptive fields and there are fewer of them
than the Where system or in the Form System
○ Our perception of color is rather coarse
○ Using outline - painters can seemingly make colors conform to shapes - even
when within those shapes - color is looser
WHY? - Not why, what!
● You already know why…
● Many reasons
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Tungsten light - with more red waves. Fluorescent light - about the same as daylight. Sodium vapor lights - very yellow * makes it hard to see color at all. We see colored shadows when an object is being lit by several color illuminations. We usually don"t notice because most changes are gradual. So they are notice by the what system. (red light + green light = white light) It is actually quite hard to distinguish color under sv lights. Emit a monochromatic light of 589 nm. We are better able to make comparisons between surfaces. Well - if we didn"t have the center surround organization. That allow us to compare the different sources of light. The same objects would look different depending on their light source. The opponent process organization allows us to perceive objects similarly in different contexts. Color mixing and color resolution (back to the what)
