1. 22.3 Using Color pp. 487 - 491 Mr. Richter

2. Agenda  Warm-Up  Review HW  Notes:  How We See Objects  Mixing Pigments (The Subtractive Color Process)

3. Objectives: We Will Be Able To…  Describe how humans see specific colors.  Explain the subtractive color process.  Determine what color of light will be reflected if a colored light is shined on a certain object.

4. Warm-Up:  Leaves are green. What makes them green? That is, why do we perceive them to be green?  Discuss at your table and we will discuss as a class in a few minutes.

5. How We See Objects

6.  An object will appear to be the color of the light that it reflects.  Green leaves appear green because they absorb all wavelengths of light except green, which they reflect.  If a red light shines on a green leaf, what color will the leaf appear to be?  Black!

7. How We See Objects  Green objects only reflect green light.  When white light shines on green objects (white light contains green), green light is reflected  When red light shines on green objects (red light contains no green), the light is absorbed, and the object appears black.  What color does the leaf appear if green light shines on it?  Green, of course!

8. Mixing Pigments The Subtractive Color Process

9. Mixing Pigments  To make objects a certain color, pigments (little specks of colored material) are mixed together.  For an object to reflect a certain color, all other colors of light must be absorbed.  This is called the subtractive color process.

10. Mixing Pigments  The subtractive color process is also called the CMYK process:  Cyan  Magenta  Yellow  blacK  These colors are the subtractive primary colors.

11. Mixing Pigments  How do you make green paint?  Mix cyan (which absorbs red)  With yellow (which absorbs blue)  If red and blue are absorbed, only green is reflected!

12. Mixing Pigments  If pure yellow light shines on a magenta t-shirt, what color will the t-shirt appear to an observer?  Yellow light = green + red light  Magenta = reflects red + blue  Yellow shining on magenta reflects only red light

13. Expert  http://www.youtube.com/watch?v=gtgBHsSzCPE http://www.youtube.com/watch?v=gtgBHsSzCPE

14. Wrap-Up: Did we meet our objectives?  Describe how humans see specific colors.  Explain the subtractive color process.  Determine what color of light will be reflected if a colored light is shined on a colored object.

15. Homework  p. 495 #8-11