18.1 Light and Color Pg. 610 - 615

When Light Strikes an Object When light strikes an object, the light can be reflected, transmitted, or absorbed Most objects can be classified into three different categories 1. Transparent 2. Translucent 3. Opaque

Transparent Materials Transmits most light that strikes it Light passes right through without being scattered Transparent materials allow you to see clearly what is on the other side Examples: Clear glass, water, air

Translucent Materials Scatters light as it passes through Can see things behind a translucent object, but the details are blurred Examples: Wax Paper & Frosted Glass

Opaque Materials Reflects or absorbs all of the light that strikes it Light CANNOT pass through Cannot see through opaque objects Examples: Wood, Metal, tightly woven fabric

The Colors of Objects The color of an object depends on two things 1. The material the object is made from 2. The color of light striking the object

Color of Opaque Objects Depends on the wavelengths of light that the object reflects The color of an opaque object is the color of the light it reflects Objects can appear to change color if you view them in different colored lights.

Color of Transparent and Translucent Objects The color of transparent and translucent objects is the color of light it transmits Transparent and translucent materials are used to make color filters Example: Lenses in sunglasses are color filters

Combining Colors Three colors that combine to make any other color are called primary colors Red, Green, Blue Two primary colors that combine in equal amounts produce secondary colors

Mixing Colors of Light When the 3 primary colors are combined in equal amounts, they produce white light If they are combined in different amounts they create other colors Examples: Red + Green = Yellow Red + Blue = Magenta

Mixing Colors of Light Any two colors that combine to create white light are called complementary colors Examples: Yellow and Blue or Cyan and Red A color television produces many colors using only the three primary colors of light By varying the brightness of each colored bar, the TV can produce thousands of colors

Mixing Pigment Inks, paints, and dyes have pigments Pigments are colored substances that are used to color other materials Pigments absorb some colors and reflect others As pigments are added together, fewer colors of light are reflected and more are absorbed The more pigments that are combined the darker the mixture looks

Mixing Pigments Primary colors of pigments are: Cyan, yellow, and magenta These colors combined in equal amounts produce black If you combine two primary colors of pigment = secondary pigments The secondary colors of pigments are red, green, blue