And Elvis said ……………Let there be Light

The Visible SpectrumThe Visible Spectrum

Prism and colors

Light and Matter

Transparent –materials that transmit light Transparent –materials that transmit light waves. waves.

Translucent – materials that transmit light Translucent – materials that transmit light but do not permit objects to be seen clearly. but do not permit objects to be seen clearly.

Opaque – Materials that absorb or reflect all Opaque – Materials that absorb or reflect all the light waves that fall on them. the light waves that fall on them.

Waves: Light and Color

Light provides a great variety of information. The eye can detect tiny changes in the size, brightness and color of an object.

A hand against a white wall illuminated by the colors red, blue and green would show the varieties of the colors both on the hand as well as displaying multicolored shadows on the wall.

R REDRED O ORANGEORANGE

Y YELLOWYELLOW G GREEN GREEN

B BLUEBLUE

I INDIGO INDIGO V VIOLETVIOLET

AND ARE THE COLORS OF THE AND ARE THE COLORS OF THE SPECTRUMSPECTRUM

PRIMARY COLORS OF LIGHT WAVES

GREEN

BLUE

RED

Additive Process of Primary Colors

• RED AND BLUE = RED AND BLUE =

magenta

RED AND GREEN=

BLUE AND GREEN =

yellow

cyan

* magenta, yellow and cyan are secondary colors

Complementary colors of light

•Light of a color and its Complementary Color add to produce White light.

If yellow light = red and green and yellow + blue = white then yellow is complementary to blue

Cyan and red are complementary colors

Magenta and green are complementary colors

Newton Color Wheel

Newton Color Wheel

Pigments and Dyes

A dye is a molecule that absorbs certain A dye is a molecule that absorbs certain wavelengths of light and transmits or wavelengths of light and transmits or reflects others. reflects others.

A pigment is like a dye. It is colored A pigment is like a dye. It is colored material that absorbs certain colors and material that absorbs certain colors and transmits or reflects others. A pigment transmits or reflects others. A pigment particle is larger than a molecule and can be particle is larger than a molecule and can be seen with a microscope. seen with a microscope.

Subtractive Process

The absorption of light forms colors by the The absorption of light forms colors by the subtractive process. subtractive process.

Molecules in pigments and dyes absorb Molecules in pigments and dyes absorb certain colors from white light.certain colors from white light.

A pigment that absorbs only one color A pigment that absorbs only one color from white light is called Primary Pigment.from white light is called Primary Pigment.

Primary Colors of Pigments

yellow magenta

cyan

SECONDARY PIGMENT COLORS

A pigment that absorbs two primary colors A pigment that absorbs two primary colors and reflects one is a secondary pigment. and reflects one is a secondary pigment.

red green blue

•Note that the primary pigment colors are the secondary light colors.

Complementary Pigment ColorsThe primary pigment yellow absorbs blue light.

If it is mixed with the secondary pigment blue that absorbs green and red light, all light will be absorbed.

No light will be reflected, so the result will be black. Yellow and blue are called complementary pigments.

Cyan and red, as well as magenta and green, are also complementary pigments.

Conclusion and Review

White light is a combination of the spectrum of White light is a combination of the spectrum of colors, each having a different wavelength. colors, each having a different wavelength.

Primary colors in light are red, blue and green. Primary colors in light are red, blue and green. Primary colors of pigments are yellow, cyan and Primary colors of pigments are yellow, cyan and magenta. magenta.