Black is the absence of all visible light. Black is NOT a color!!!

Transcription

1 Black is the absence of all visible light. Black is NOT a color!!!

2 This is why white colored clothing is cooler in summer. White fabric re emits light, while black fabric absorbs light.

3 Why do we see this shirt as red?

4 Why do we see this shirt as red? Absorbed Light: Re emitted Light:

5 Why is this shirt yellow?

6 Why is this shirt yellow? Absorbed Light: Re emited Light:

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8 As you may know, this doesn't work for paint! Here's why:

9 As you may know, this doesn't work for paint! Here's why: Paints and dyes contain... PIGMENTS: finely divided solid particles that absorb light of certain frequencies, and reflect light of other frequencies.

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11 paint looks paint looks blue because it blue because it ABSORBS certain colors while REFLECTS others. ABSORBS certain colors while REFLECTS others.

12 paint looks paint looks blue because it blue because it ABSORBS certain ABSORBS certain colors while colors while REFLECTS others. REFLECTS others.

13 paint looks paint looks yellow because it ABSORBS certain yellow because it ABSORBS certain colors while REFLECTS others.

14 paint looks paint looks yellow because it ABSORBS certain colors while yellow because it ABSORBS certain colors while REFLECTS others.

15 Mixed paint will absorb whatever colors absorb whatever colors are absorbed by the red are absorbed by the red and yellow paints. and yellow paints.

16 Mixed paint will absorb whatever colors absorb whatever colors are absorbed by the red are absorbed by the red and yellow paints.

17 Mixed paint will Mixed paint will absorb whatever colors absorb whatever colors are absorbed by the red are absorbed by the red and yellow paints. and yellow paints.

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19 paint looks paint looks because it because it ABSORBS certain colors while REFLECTS others. colors while REFLECTS others.

20 paint looks because it because it ABSORBS certain colors while colors while REFLECTS others. REFLECTS others.

21 Mixed paint will Mixed paint will absorb whatever colors are absorbed by the red are absorbed by the red and blue paints. and blue paints.

22 Mixed paint will Mixed paint will absorb whatever colors are absorbed by the red are absorbed by the red and blue paints. and blue paints.

23 Mixed paint will absorb whatever colors are absorbed by the red and blue paints. Mixed paint will absorb whatever colors are absorbed by the red and blue paints.

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26 Here's where this type of color mixing runs into problems:

27 Here's where this type of color mixing runs into problems:

28 Here's where this type of color mixing runs into problems:

29 Black gives some reflection, but no significant re emission:

30 In fact, usually mixing these 'primaries' usually results in more of this color:

31 Luckily, black pigment pigment that absorbs all frequencies equally is fairly common in nature. THANKS CARBON!!!

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33 Whereas we refer to the mixing of colored light as color mixing by addition, we refer to the mixing of pigments as color mixing by subtraction. vs.

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35 SUBTRACTIVE COLOR MIXING: PIGMENT ABSORBS RE EMITS YELLOW MAGENTA CYAN RED GREEN BLUE

36 SUBTRACTIVE COLOR MIXING: PIGMENT ABSORBS RE EMITS YELLOW BLUE LIGHT RED & GREEN LIGHT MAGENTA GREEN LIGHT RED & BLUE LIGHT CYAN RED LIGHT GREEN & BLUE LIGHT RED GREEN & BLUE LIGHT RED LIGHT GREEN RED & BLUE LIGHT GREEN LIGHT BLUE RED & GREEN BLUE LIGHT

37 Even though we think of blue, yellow, and red as the primary colors of our youth, in reality, what are the 3 most useful colors to have when performing color mixing by subtraction?

38 SUBTRACTIVE PRIMARY COLORS: YELLOW MAGENTA CYAN YMCK

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40 Low Frequency High Wavelength Visible Light Region of the Electromagnetic Spectrum High Frequency Low Wavelength Subtractive Color: 6.5x10 14 Hz 5.5x10 14 Hz 4.5x10 14 Hz Infrared 0.7μm 0.6μm 0.5μm 0.4μm c = v = λf Ultra Primary Colors Secondary Colors Tertiary Colors

41 The Fan Demo:

42 The Fan Demo: In addition to revealing to true colors of the fan blades, the strobe light makes fan blades appear to be stationary, or even to move backwards. Why?

43 P LED Rims.wmv h ysics