group 3 st. angela - colors

COLORS

REFLECT ORABSORB?

____ RED

____ ROY GIV

____ ROY GBIV

____ GREEN

____ ROY GBIV

YELLOW, CYANOR MAGENTA?

BLUE +

GREEN

BLUE +

RED

RED +

GREEN

What is COLOR?COLOR is a physiological and psychological response to the wavelengths of light entering

the retina.

VISIBLE LIGHTSPECTRUM

VISIBLE LIGHT SPECTRUM•Situated between Infrared Light and Ultraviolet Light•Consists of a spectrum of wavelengths that range from 700 nanometers to 400 nanometers approximately•Also known as ROYGBIV or the Color Spectrum•Each individual wavelength within the spectrum represents a color

DISPERSION – separation of visible light into different wavelengths/colors

RED – longest wavelength and lowest frequency in the Color Spectrum

VIOLET – shortest wavelength and highest frequency in the Color Spectrum

BLACK – absence of the wavelengths of the visible light spectrum

WHITE – seen when all the wavelengths of the spectrum are perceived by the eye ; combination of all the colors in the spectrum

How is color perceived by the eye?

•As the light enters the eye, it strikes the retina which is lined with sensitive cells known as rods and cones.•Rods – sensitive to the intensity of light but cannot distinguish between the different wavelengths•Cones – color-sensing cells of the retina; there are 3 type of cones, each sensitive to a range of wavelengths in the spectrum

•RED CONE – sensitive to the lower frequencies ROY

•GREEN CONE – sensitive to the middle frequencies

•BLUE CONE – sensitive to the higher frequencies

COLOR BY REFLECTIONAND

COLOR BY TRANSMISSION

When a light wave strikes upon an object, the different

frequencies of light are either absorbed or

reflected/transmitted.When can you tell when a frequency of light is absorbed or reflected/transmitted?

SELECTIVE ABSORPTION OF LIGHT:•Occurs when the frequency of the incident light is the same as the frequency at which the atoms of the object vibrate•When a frequency of light is absorbed, it is not seen or observed in an object.•Objects have different colors because they contain different pigments which absorb one or more frequencies of light.

Ex. In a red object illuminated by white light, the OYGBIV components of the incident light is not observed. OYGBIV are the absorbed frequencies of light.

When the frequency of the incident light wave does not match the

frequency at which the atoms of the object move, reflection and transmission of light occurs.

Important components in determining the color of an object:

• INCIDENT LIGHT• KIND OF PIGMENT IN THE OBJECT

(or what colors are absorbed by the pigment)

**As to why, this will be discussed further in the topic of Color Addition and Subtraction.

COLOR BY REFLECTION•Occurs when the frequency of the

incident light is not the same as the frequency at which the atoms of the

opaque object vibrate• The color of the object depends on the

frequency of the light wave that is reflected.Ex. In a red opaque object illuminated by white light, RED LIGHT is reflected and it is the color we perceive. OYGBIV was observed therefore you cannot perceive it.

WHAT ABOUT BLACK AND WHITE OBJECTS?•When an object is black, all the colors of the spectrum are absorbed by pigment in the object.

•When an object is white, all the colors of the spectrum are reflected and nothing is absorbed.

COLOR BY TRANSMISSION•Occurs when the frequency of the

incident light is not the same as the frequency at which the atoms of the translucent/transparent object

vibrate• The color of the object depends on the

frequency of the light wave that is transmitted.Ex. In a red glass illuminated by white light, RED LIGHT is transmitted through. OYGBIV was absorbed by the pigment in the glass.

Why is window glass colorless?- It transmits light of all visible

frequencies and does not absorb any frequency of light.

COLOR ADDITIONAND

COLOR SUBTRACTION

COLOR ADDITION

- the process of adding two or more colors for production of a new color

White light is not only produced by combining all the frequencies of the color spectrum.

White light can is also produced by

combining the primary colors of light: red, green,

blue.

ADDITIVE PRIMARY COLORS OF LIGHT

RED GREEN BLUE

When two primary colors of light: red,

green, blue are added, secondary colors of light are

produced. The secondary colors of

light are yellow, cyan and magenta.

SECONDARY COLORS OF LIGHT

BLUE + GREEN = CYANBLUE + RED = MAGENTABLUE + GREEN = YELLOW

COMPLEMENTARY COLORS OF LIGHT-two colors of light (one primary, one secondary that together, in equal

intensities produce white light-the complementary colors of light are magenta & green, cyan & red and yellow & blue.

magenta + green cyan + red yellow + blue

(red + blue) + green (green + blue) + red (red + green) + blue= white = white = white

COLOR SUBTRACTION

-the process of determining the resulting color of an object through subtracting from the frequencies in incident light the frequencies that are absorbed by the pigment in the object

Important components in determining the color of an object:

• INCIDENT LIGHT• KIND OF PIGMENT IN THE OBJECT

WHY?

The kind of pigment of the object determines what colors it absorbs from the incident light. The color that is not absorbed (or subtracted) is the resulting color.

SUBTRACTIVE PRIMARY COLORS OF LIGHT & PRIMARY COLORS

OF PAINT YELLOW MAGENTA CYAN

absorbs blue light absorbs green light absorbs red light

-when you add two subtractive primary colors, you get an additive primary color as a result- when you add all subtractive primary colors, you get BLACK

YELLOW MAGENTA CYAN

-GREEN = RED-RED = GREEN

•The color thatYELLOW LIGHTcan absorb isBLUE

-RED = BLUE- BLUE = RED

•The color thatMAGENTA LIGHTcan absorb isGREEN

-BLUE = GREEN-GREEN = BLUE

•The color thatCYAN LIGHTcan absorb isRED

Complementary Colors and Color Subtraction

-the color of the light absorbed by a pigment is the complementaryColor of that pigment

PIGMENT ABSORBSBLUE YELLOW ( RED & GREEN )

YELLOW ( RED & GREEN ) BLUE

GREEN MAGENTA (BLUE & RED)

MAGENTA (BLUE & RED) GREEN

RED CYAN (GREEN + BLUE)

CYAN (GREEN + BLUE) RED