Post on 24-Dec-2015
transcript
Colour Theory
White light is composed of all the colours of light
White colour can be created by combining the three PRIMARY colours (red, green, and blue) of light in equal parts
Additive Colour Theory
SECONDARY Colours are created by combining only two of the three primary colours of light in equal parts
Red light and blue light produces magenta
Red light and green light produces yellow
Blue light and green light produces cyan
The additive colour theory applies to SOURCES of light
When light hits an object some wavelengths of light are reflected and others are absorbed, or subtracted
The colour that you see when you look at an object is the colour of the light that object reflects
A pigment is a chemical that absorbs some colours of light and reflects other colours of light
Subtractive Colour Theory of Light
Black objects absorb all colours
White objects reflect all colours
Blue objects reflect blue and absorb all other colours
PRIMARY subtractive colours are cyan, magenta, and yellow
The opposite of the additive colour theory of light
Subtractive Colour Theory
Secondary colours are red, green, and blue
The subtractive colour theory applies to pigment and dyes and the colours they absorb
Subtractive Colour Theory of Light
We see the colour cyan because red light is absorbed and green and blue are reflected to produce cyan
How subtractive colours reflect light
We see the colour magenta because green light is absorbed and red and blue are reflected to produce magenta
How subtractive colours reflect light
We see the colour yellow because blue light is absorbed and green and red produce yellow
How subtractive colours reflect light
White Light (R+ G + B)
Yellow absorbs Blue (B)
Red and Green light is
reflected,
therefore flower
appears YELLOW
Magenta Light (R+ B)
Yellow absorbs Blue (B)
Red light is
reflected,
therefore flower
appears RED
Cyan Light (G + B)
Yellow absorbs Blue (B)
Green light is
reflected,
therefore flower
appears GREEN
Cyan Light (G + B)
Red absorbs Green and Blue
NO light is
reflected,
therefore flower
appears BLACK
Yellow Light (R + G)
Red absorbs Green and Blue
Red light is
reflected,
therefore flower
appears RED
Yellow Light (R + G)
Green absorbs Red and Blue
Green light is
reflected,
therefore flower
appears GREEN
Cyan Light (G + B)
Green absorbs Red and Blue
Green light is
reflected,
therefore flower
appears GREEN
Yellow Light (R + G)
Blue absorbs Red and Green
NO light is
reflected,
therefore flower
appears BLACK
Magenta Light (R + B)
Blue absorbs Red and Green
Blue light is
reflected,
therefore flower
appears BLUE
Cyan Light (G + B)
Blue absorbs Red and Green
Blue light is
reflected,
therefore flower
appears BLUE
White Light (R+ G + B)
Yellow absorbs Blue (B)
Red and Green light is
reflected,
therefore T-shirt
appears YELLOW
Cyan Light (G + B)
Blue absorbs Red and Green
Blue light is
reflected,
therefore T-shirt
appears BLUE
Cyan Light (G + B)
Red absorbs Blue and Green
NO light is
reflected,
therefore T-shirt
appears BLACK
Additive Colour Theory
Subtractive Colour Theory
COLOUR THEORY
Primary and Secondary ADDITIVE Colour Theory in a nutshell
Primary and Secondary SUBTRACTIVE Colour Theory in a nutshell
Utilize pp. 386 to 388 to answer the following questions p. 388 # 1, 2, 3, 4, 5
Learning Checkpoint
1) The wavelength or frequency determines the colour.
2) Red, orange, yellow, green, blue, and violet are six general categories of colour.
3) The visible spectrum is the part of the electromagnetic spectrum that the human eye can see – it goes from red through violet.
Learning Checkpoint Answers
4) Each of the visible colours of light can be approximated by an appropriate mixture of red, green, and blue light.
5) Each of the visible colours of pigments can be approximated by an appropriate mixture of magenta, cyan, and yellow pigments.
Learning Checkpoint Answers