Additive Colour Theory

Brain Teaser Red and green light make yellow light. Blue and green light make cyan light. Red, green and blue light make white light. Red and blue light make magenta.

Green and red light make cyan light. Green and blue light make magenta light. Blue, red and green light make white light. Blue and green light make yellow.

Today’s Objectives: Learn how colours of light work Understand what “additive colour theory” means Know what primary, secondary and complimentary colours are

Primary Colours of Light - Mixing red, green and blue lights together creates white light. These 3 colours are called PRIMARY colours Cannot create these 3 colours from other colours Can be used in combination to create the colours of the spectrum

Secondary Colours of Light These colours are created by combining two of the primary colours Cyan Magenta Yellow

Additive Colour Theory The theory that combining the three primary colours of light produces white light Combining 2 primary colours produces secondary colours of light

Red + Green + Blue = White Red + Green = Yellow Green + Blue = Cyan Red + Blue = Magenta

Human Vision The human eye detects shapes, movements and the primary colours of light. Back of eye = retina - each retina has 2 types of light-sensitive cells (rods & cones) - each retina has millions of rods and cones

Rods & Cones Rods detect low levels of light. Once our eyes adapt to low light we can see shapes Red light does not interfere

Cones are less sensitive to light than rods Cones allow us to see colour 3 types of cones (one for each primary colour of light)

Colour Additive Theory in Technology Digital Cameras Computer monitors TV screens *pixilation

Cameras Color filters work by absorbing certain colors of light, letting the remaining colors through. They can be used to demonstrate the primary colors that make up an image.

Red/Green Colour Blindness Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under lighting conditions when color vision is not normally impaired More common in males (carried on X chromosome)

WORKSHEET Read p. 434-438