1. 4.3 Mixing Colours (p294-299) (p294-299)

2. Primary Colours The 3 primary colours can be combined to generate any other colour: Red Green Blue

3. 3 Colours The millions of colours on a computer monitor or TV screen are produced with only 3 colours. Your eyes have 3 types of colour-receiving cone cells that respond to colours of light.

4. Try this on page 295

5. How Do Your Eyes Work? Each of the 3 types of cells in your eyes that are sensitive to colour respond to certain wavelengths. Your brain combines the information to “see” the correct colour. Light-sensitive cells in the retina

6. Mixing Colours Primary Colours - 3 colours that, when combined, can make any other colour. -primary colours can be additive or subtractive (they can be added together or taken apart). -See Figure 4.13 (p296) – ask your neighbour to hold up your textbook

7. (4.3) Mixing Colours Additive Primary Colours - When the 3 additive primary colours are shone together, white light is produced where they overlap. - Where only 2 of the additive primary colours overlap, you see additive secondary colours.

8. Additive Primary Colours 3 colours

9. Additive Primary Colours 2 colours

10. Complementary Colours - are a primary colour and the secondary colour created by mixing the other two primary colours. - are opposite each other in the colour chart to the right

11. Homework (4.3) Mixing Colours -WB p122-123

12. 4.3 Mixing Colours (p294-299)....more (p294-299)....more

13. (4.3) Pigments There are 3 subtractive primary colours: cyan, magenta, and yellow. A variety of combinations of these 3 colours can subtract light from white light to produce nearly any colour. Pigments can subtract colours.

14. Pigments Printer ink consists of black, cyan, magenta, and yellow ink only. How can we print such a wide variety of colours?

15. Subtractive Primary Colours The colours produced by subtracting equal amounts of 2 of the 3 subtractive primary colours are called subtractive secondary colours.

16. Subtractive Primary Colours Black is produced by subtracting equal amounts of the 3 subtractive primary colours. The “code” for black is K so as not to be confused with blue.

17. colour wheel - summarizes the relationships among additive and subtractive primary, secondary, and complementary colours. More Colours

18. Diagrams illustrate how colours are subtracted from white light when it hits a material of a certain colour. Diagrams

19. So, how do we actually “see” colour? Your eyes have three types of cone cells One type detects red, one type detects blue and one type detects green (due to the different wavelengths of the colours) Your brain combines the information to “see” the correct colour Colour blindness can be caused when one or more cone cells are not working properly

20. Can you see all of the numbers?

21. Homework (4.3) Pigments -WB p124-127 -Text p299 LC #1-3 p 303 #2, 5, 8, 9 Now try these! -Activity 4.6 (p301) -Activity 4.7 (p302) Hand in Today