Color Subtraction Example: –Newspapers and the new zip-lock sandwich bags use color subtraction.

• Color Subtraction Example: – Newspapers and the new zip-lock

sandwich bags use color subtraction.

White

Red

Green

Blue

Yellow

Cyan

Magenta

Primary Colors

Green

Pure Green

Color AdditionPrimary Green

Why is the sky blue?Why is the sky blue?

• Nitrogen and Oxygen in our atmosphere scatter high frequencies of light.

Why are sunsets red?Why are sunsets red?• Red light is scattered the least by our

atmosphere.

• The greatest path of sunlight through the atmosphere is at sunset or sunrise.

Why are clouds white?Why are clouds white?

• The color of light scattered by clusters of water molecules vary with the size of the clusters.

• The size of clusters of water molecules (droplets) vary in clouds.

Why is the ocean Why is the ocean greenish blue?greenish blue?

• Red light is absorbed by the molecules in the water.

Color VisionColor Vision• Colorblindness - about 10% of population• Red-green is predominant• Yellow-blue - a few• Total - some

• Complementary Colors - any two colors that add together to produce white

• e.g. magenta + green = white

Optical Illusions

Animation