1. Andrew Hanson & Michael de Podesta
Colour
Andrew Hanson & Michael de Podesta
February 2013

2. The Simple Story
Top 7 questions about colour 6: what are the primary colours?

3. Light is not coloured!
Top 7 questions about colour 6: what are the primary colours?

6. Colour is a human sensation
Top 7 questions about colour 6: what are the primary colours?

7. Primary colours Sets of ‘elemental’ colours that:
can be used to make all colours,
that can’t be combined to make each other.
Top 7 questions about colour 6: what are the primary colours?

8. Typical TV
Typical print
Good print

9. What are the primary colours?
Top 7 questions about colour 6: what are the primary colours?

10. Magenta subtracts green
Subtracting light
Magenta subtracts green C M Y K R G B

12. The not-so Simple Story
Top 7 questions about colour 6: what are the primary colours?

13. Afterimages
Do you have trouble with elephants here? We do at NPL, so we have this sign up. I took the sign and changed it to this pink one.
Colour is something you see. In this demo I’ll prove it is something to do with your eyes. Stare at the small square in the elephant and don’t move your eyes. After a while the edges of the image will start to feel liquidy and your eyes will become a bit tired. It’s not often you actually stare at things like this as your eyes normally move about a lot.
Now I shall switch off the image and you will see an image that really isn’t there. What colour is it.
The colour you see is called the complementary to the original colour. It is an ‘opposite’ colour, and when mixed with the original colour will make white.
Everyone’s colour will be slightly different as everyone’s eyes are a bit different.
Now I’ll do it with another image. I chose these colours by making the afterimage I saw after looking at the original. You can make these at home. You need to look at them under bright light for best results, and the afterimages appear anywhere – even on the ceiling or with your eyes shut.
What’s happened is that sensors in your eyes became used to seeing colour so got bored and stopped sending signals – so greeny-blue appeared less greeny-blue than it really was – I.e. redder. When we looked at a blank screen the effect was still there for a while so that part of your eye saw everything redder than it really was. Greeny-blue (cyan) and red are a complementary colour pair

14. Optical illusions

15. Inspired by Beau Lotto www.lottolabs.org

16. Designed by Akiyoshi Kitaoka
From

17. Designed by Akiyoshi Kitaoka
From

18. Inconstencies of colour vision 1: Age
HANDS BEHIND BACK IMAGE
Chameleonic colour, 2: Age

19. Chameleonic colour, 2 lighting level.
Light Level
Chameleonic colour, 2 lighting level.
Violets/bluebells at dusk
Chameleonic colour, 3: lighting level.