Color

Adding Colors White light can be split up to make separate colors. These colors can be added together again. The primary colors of light are red, blue and green: Adding blue and red makes magenta (purple) Adding blue and green makes cyan (light blue) Adding red and green makes yellow Adding all three makes white again

Only red light is reflected Seeing color The color an object appears depends on the colors of light it reflects. Pigments absorb colors, reflecting or transmitting only some For example, a red pigment book only reflects red light: Homework White light Only red light is reflected

Subtracting Colors Pigments absorb colors, that is they subtract colors Mixing all pigment results in no color That is Black! The “Primary colors” of your youth were really the primary pigments Or “Subtractive” colors

A pair of purple trousers would reflect purple light (and red and blue, as purple is made up of red and blue): Purple light A white hat would reflect all seven colours: White light

Using filters Filters use pigments to “block” out different colors of light: Red Filter Magenta Filter

Using Colored light What color we see depends as much on the colors of light hitting an object as the pigments in it For example, consider a soccer uniform: Shirt looks red White light Shorts look blue

In different colours of light this uniform would look different: Red light Shirt looks red Shorts look black Shirt looks black Blue light Shorts look blue