cs781 - Colour for Computer Graphics - Winter 2012

Course Notes

Lecture 21 - Functional Use of Colour

And Now from our Sponsor

  1. Projects
  2. Tables of useful colour data
  3. My deadline for grade submission is May 1st.
  4. Joseph Albers Interaction of Color is in the Rare Book Room of the Dana Porter Library.

What is Special about Colour?

Why do animals create the capability of seeing colour? Why do plants make parts of the plant colourful?

That is, colour and colour vision co-evolve allowing animals and plants to specialize.

To do so, plants must mark the things that animals want, commonly by colouring them.


  1. Pollination
  2. Seed Distribution

Lots of evidence showing that colour and shape are combined very effectively.

Other Uses of Colour in the Natural World

  1. Finding a mate
  2. Making a disguise
  3. Advertising

Human Interference in Natural Colour

Patterning of colour is controlled by a very small number of genes, which makes it easy for plant breeders

Human Taste in Colour

explored in the fruit and vegetable section of a grocery store


  1. Go to a big grocery store, like Zehr's or Sobey's
  2. Look at the fruit asking what do the fruit/vegetables that look good to eat have in common
  3. Buy a few nice-looking ones.
  4. Take them home and wait until dark
  5. Turn on your kitchen light and try to remember the colour they were at the store.

The same thing works, though somewhat differently, with meat.

How does this Specialness Manifest itself in Human Perception and Cognition?

Visual Search for a Specific Colour

Solving Occlusion Problems Using Colour

Making Colour Work for You

1. Finding is much more common task than you think

2. Solving occlusion problems is much more common than you think

3. Grouping things together using colour is very common

Some hints for doing it better

  1. Colour is a property of areas, not of lines
  2. Use visually distinct characteristics

    If they look distinct to you they probably are distinct.

  3. Pattern, another property of areas, goes well with colour
  4. Legends are effective for attaching meaning to colour.

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