Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring...
-
Upload
esmond-mcdonald -
Category
Documents
-
view
221 -
download
1
Transcript of Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring...
![Page 1: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/1.jpg)
Chapter 27
Color
![Page 2: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/2.jpg)
1. SELECTIVE REFLECTION
• Most objects "reflect" rather than emit light.
• The spring model of the atom works well in explaining reflection.
• Radiations that match the resonant frequencies of the atoms are absorbed.
• Frequencies of the radiations on either side of the resonant frequencies are “reflected.”
![Page 3: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/3.jpg)
• Objects can only reflect the light that is in
the source illuminating the object.
• Demo – Razorback Football in Cyan Light Demo – Razorback Football in Cyan Light (Next Slide) (Next Slide)
![Page 4: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/4.jpg)
![Page 5: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/5.jpg)
2. SELECTIVE TRANSMISSION
• As light passes through materials some frequencies of light are removed (absorbed) while other frequencies are transmitted.
• The degree of transmission depends on how transparent the material happens to be.
![Page 6: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/6.jpg)
• Color filters are good examples of selective
transmission.
• Demo – Color Filters and White LightDemo – Color Filters and White Light
![Page 7: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/7.jpg)
3. MIXING COLORED LIGHT
• All visible frequencies make up white light.
• Example: The sun emits all frequencies and its
light is white.
• (Actually it is slightly yellowish to us on Earth,
which possibly explains why we are more
sensitive to light in the middle of the spectrum.)
![Page 8: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/8.jpg)
Color Addition
![Page 9: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/9.jpg)
Through color addition you are able to see a wide
range of colors from a color TV or color projector
which actually only emit three different colors.
These colors are red, green, and blue.
They are called the additive primaries.
![Page 10: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/10.jpg)
Your vision system “adds” these together to see
single colors from a single location illuminated by
more than one color.
You even see colors that don’t appear in the
continuous emission spectrum of the sun.
Red, green, and blue are used as the additive
primaries because this set of three will produce the
widest range of colors that you visually
experience.
![Page 11: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/11.jpg)
On the next slide you will see what happens as you add colors to produce other colors.
![Page 12: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/12.jpg)
Note that cyan is the addition of green and blue.
Note that yellow is the addition of red and green.
White
Red
Green
Blue
Yellow
Cyan
Magenta
Colors in White Light
Note that magenta is the addition of red and blue.
You can see that these three add to give white.
![Page 13: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/13.jpg)
To summarize, see color addition circles on next slide.
![Page 14: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/14.jpg)
Color Addition Circles
This is what you would get with three partially overlapping spotlights reflecting off of a white screen.
![Page 15: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/15.jpg)
Complementary Colors
• Any two colors that add to give white are
said to be complementary colors.
• Demo - Complementary ColorsDemo - Complementary Colors
![Page 16: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/16.jpg)
4. MIXING COLORED PIGMENTS
• Subtractive primaries - YELLOW,
CYAN, and MAGENTA
• Example - Mixing paints, zip-lock
sandwich bags, color printing
• Demo - Color SubtractionDemo - Color Subtraction
• Overhead - Foretravel AdvertisementOverhead - Foretravel Advertisement
![Page 17: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/17.jpg)
Color Subtraction
![Page 18: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/18.jpg)
Through color subtraction you are able to see a
variety of colors from printings, paintings, etc.
If you have ever bought printer inks, you will
notice that the ones used to provide a variety of
colors in printing are yellow, cyan, and magenta.
They are called the subtractive primaries.
![Page 19: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/19.jpg)
In subtraction, colors are eliminated by the
absorption of colors that were in the original
illuminating source.
This particular set of three colors, yellow, cyan,
and magenta, will produce the widest range of
colors that you visually experience.
![Page 20: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/20.jpg)
On the next slide you will see what happens as you remove different colors from white light.
![Page 21: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/21.jpg)
White
Yellow
Take away yellow and what is left?
You get blue.
Blue
Colors in White Light
![Page 22: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/22.jpg)
WhiteRed
Take away cyan and what is left?
Cyan
You get red.
Colors in White Light
![Page 23: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/23.jpg)
Magenta
White
Take away magenta and what is left?
You get green.
Green
Colors in White Light
![Page 24: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/24.jpg)
To summarize, see color subtraction circles on next slide.
![Page 25: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/25.jpg)
Color Subtraction Circles
This is what you would get with three partially overlapping transparencies on an overhead projector.
Slide - Raincoat ClosetSlide - Raincoat Closet
![Page 26: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/26.jpg)
• It should be noted from the previous that objects that reflect a particular color are themselves good absorbers of the complimentary color of that particular color.
• For examples:
• A red object is a good absorber of cyan and vice versa.
• A blue object is a good absorber of yellow and vice versa.
• A green object is a good absorber of magenta (blues and reds) and vice versa.
![Page 27: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/27.jpg)
5. WHY THE SKY IS BLUE
• One man’s view.• Just as resonating tuning forks scatter sound, so do
particles in our atmosphere scatter light.
• N2 and O2 scatter high frequencies which are near natural frequencies of N2 and O2.
• (Natural frequencies are in the UV.)• This scattering produces the bluish sky.• The blue end of the spectrum is scattered ten times better
that the red end.
![Page 28: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/28.jpg)
Blue in this direction
Sun
Earth
Top of Atmosphere
![Page 29: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/29.jpg)
6. WHY SUNSETS ARE RED
• If the atmosphere becomes thicker or the paths
of light through the atmosphere become longer,
more of the longer wavelengths of light will be
scattered.
Sunset
• Demo - Blue Sky and Red SunsetDemo - Blue Sky and Red Sunset
• Because of scattering of blue light the sun
appears more yellowish at noon than it really is.
Earth
Sun
Sun
![Page 30: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/30.jpg)
7. WHY CLOUDS ARE WHITE
• Droplet size dictates which colors are
scattered best.
• Low frequencies scatter from larger particles.
• High frequencies scatter from small particles.
![Page 31: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/31.jpg)
• Electrons close to one another in a cluster
vibrate together and in step, which results in a
greater intensity of scattered light than from the
same number of electrons vibrating separately.
• Large drops absorb more and scatter less.
![Page 32: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/32.jpg)
8. WHY WATER IS GREENISH BLUE
• Water quite often looks bluish.
• This is due to reflected “sky light.”
• A white object looks greenish blue when
viewed through deep water.
![Page 33: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/33.jpg)
• Water is a strong absorber in IR and a little in
red.
• Remove some of the red and cyan is left.
• Crabs and other sea creatures appear black in
deep water.
![Page 34: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/34.jpg)
9.9. COLOR VISION ANDCOLOR VISION ANDCOLOR DEFICIENCYCOLOR DEFICIENCY
• Colorblindness (color deficiency) affects
about 10% of population
• Red-green is predominant• Yellow-blue - a few
• Total – some
• Slide – Colorblindness Tests – Slide – Colorblindness Tests – URL
![Page 35: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/35.jpg)
10. AFTER IMAGES
• Slides - After Images - After Images
• After images are due to conal fatigue.
• Cones that have been “firing” for a while will
not “fire” as well as “rested” cones when all
are exposed to white light.
![Page 36: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/36.jpg)
Chapter 27 Review Questions
![Page 37: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/37.jpg)
Most of the light that we see has undergone
(a) selective interference
(b) selective transmission
(c) selective reflection
(d) selective refraction
(c) selective reflection
![Page 38: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/38.jpg)
A mixture of magenta and green lights give white light. These two colors are
(a) additive primaries
(b) secondary colors
(c) complementary colors
(d) fluorescent colors
(e) interference colors
(c) complementary colors
![Page 39: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/39.jpg)
Mixing yellow paint and magenta paint gives what color?
(a) red
(b) green
(c) blue
(d) cyan
(a) red
![Page 40: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/40.jpg)
What color would red cloth appear if it were illuminated by cyan light?
(a) cyan
(b) red
(c) yellow
(d) green
(e) black (e) black
![Page 41: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/41.jpg)
The sky is blue because air molecules in the sky act as tiny
(a) mirrors which reflect only blue light
(b) resonators which scatter blue light
(c) sources of white light
(d) prisms
(e) none of these
(b) resonators which scatter blue light
![Page 42: Chapter 27 Color 1.SELECTIVE REFLECTION Most objects "reflect" rather than emit light. The spring model of the atom works well in explaining reflection.](https://reader035.fdocuments.us/reader035/viewer/2022062408/56649f255503460f94c3bb2c/html5/thumbnails/42.jpg)
When you stare at a red object for a long time without moving your head and eyes and then suddenly look away at a white screen, you will see a image of the object.
(a) red
(b) blue
(c) cyan
(d) green
(e) white
(c) cyan
To Chapter 28