Parkland Junior High School 20122013 Color and Vision When all the colors of the rainbow are combined we do not see any particular color All we see is light without any color We call this combination of all the colors of light ID: 415051
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Slide1
Additive Primary Colors and Subtractive Primary Colors
Parkland
Junior High School
2012-2013Slide2
Color and Vision
When all the colors of the rainbow are combined, we do not see any particular color. All we see is light without any color.
We call this combination of all the colors of light
"white light”.Slide3
How we see colorThe retina of the human eye contains two types of cells that respond to light.
Cells called
Rods
detect the presence of light. Cells called
Cones
detect color.
There are 3 types of cones, each type of cone responds to a different color. Slide4
How we see color.
The cones in the human eye respond mainly to
red
, green, and blue
light. This is why the eye can be tricked into thinking that a beam of light is
white
when it contains only those three colors. This is also why all other colors are seen by the eye in terms of the relative amounts of red
,
green
, and
blue
light sensed by the cones.
Signals form all 3 types of cone cells and rod cells travel along the optic nerve to the brain. The brain interrupts the shape and color of an object you see. Slide5
Color Blind?
If a person has defective cone cells. They have difficulty detecting some colors. This is know as
colour blindness.Slide6
Color blind impressionsSlide7
Additive Colors
We see with our eyes the colors created by the natural light in the world. These colors are known as additive colors. The term "additive" refers to the mixing of light.
First described by James Clark Maxwell in the mid 1800s, the Color Additive Theory describes how we perceive color and how they are created. Slide8
Additive Primary Colors
Essentially
white light
is a combination of many different colors, a continuum of wavelengths organized into “bands” which we label with names (blue,
green
,
red, etc.)When equal amounts of
red light,
green light,
and
blue light
are mixed together they produce
white light.
Because you
add
the colors together to get
white
the colors that are added are known as the
A
dditive
Primary Colors.Slide9
Additive Primary Colors
Red
,
green, and blue
(
R
GB) are known as the
additive primary colors
of
white light
.
The light of two additive primary colors will produce a
secondary color
.
The secondary colors are
yellow
,
cyan
, and
magenta. These are the “additive” combinations.Slide10
The use of additive
primary
colors
in everyday life, e.g. computer monitors, televisions, and human vision.Slide11
Subtractive Primary Colors
So, if one of the additive primaries are removed, the color of the light changes. For example, if the
red light
were removed, equal amounts of blue and
green
light would make
cyan light. Equal amounts of green and
red
light would make
yellow
light, and equal amounts of
red
and
blue
light will make
magenta
light.Slide12
Subtractive Primary Colors
Yellow
,
cyan, and magenta (
C
M
Y) are called
subtractive primary colors
because some portion of
white light
has been
removed
in order to produce each color.
When all 3
subtractive primary colors
are combined they produce blackSlide13
The use of
subtractive
primary
colors
in everyday life, e.g. color printers and printer color inkSlide14
Answer the following...
The three initial colours used are called the primary additive colours. What are they?
What secondary colours were created when only two of the primary colours were blended?
What colour was created when all three primary colours were combined?
What colour was created when all three secondary colours were combined?Slide15
Answers...
(
blue
, red, and green)
(
magenta
, cyan,
yellow
)
(
white
)
(
black
)
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