Investigating Color In the Classroom

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Investigating ColorIn the Classroom

• Created for CVCA Physic
• By
• Dick Heckathorn
• 15 May 2K 5

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2 Spectrum of Light 7 Mixing Colors by
Addition 22 Mixing Colors by Subtraction
Define 27 Colored Filters 45 Primary Colors from
C, M, Y 48 Color Printing 51 Mixing Paints 56
Physicists vs Artists 60 Illuminating Using
Colored Light
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I. The Spectrum of Light

• A. White light can be separated into different
  colored lights called the spectrum.
• 1. Inv How can a prism be used to separate
  white light into its component colors?
• Look through a prism.
• Shine ray of light into prism
• Rotate prism as light passes through.

Light Box Power Source Extension Cord - Prism
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I. The Spectrum of Light

• Demo-Disc What does the prism do to the light?
• a. Shine light through single slit into a prism.
• b. Block out all but red light.
• c. Add second prism.
• d. Mount second prism beyond first.

Prism Projector Aluminum Slide Red Filter
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I. The Spectrum of Light

• How can a diffraction grating be used to separate
  white light into its component colors?
• Look through a grating at a showcase bulb.
• b. Look at spectrum using cardboard with slit on
  overhead and with grating fastened to overhead
  lens.

Grating Showcase Bulb Socket and Cord
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II. Mixing Colors By Addition

• Different colored lights overlapping on a white
  surface are perceived by the eye-brain system as
  the additive combination of the individual
  colors.
• 1. What happens when colors of light are mixed?
• a. Use ray box to observe the overlapping of
  light from red, green and blue filters.

Ray Box Color Filters Extension Cord
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II. Mixing Colors By Addition

• b. Demonstrate Overlap colors using projector
  and 3 mirrors
• c. Mount color wheel on wall.

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II. Mixing Colors By Addition

• 2. What happens when primary colors of light are
  overlapped?

R G ? ?
Yellow
R B ? ?
Magenta
G B ? ?
Cyan
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II. Mixing Colors By Addition

• 3. What happens when opposite colors of light are
  overlapped?

B Y ? ?
White
R C ? ?
White
G M ? ?
White
When two colors are added together that produces
white light, we call them complementary colors.
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II. Mixing Colors By Addition

• B. What Are Colored Shadows?
• a. Look at shadows produced using red, green and
  blue filters with ray box first individually and
  then in combinations of first 2 and then 3.
• b. Look at shadow produced using light from
  overhead or projector.
• c. Look at shadow produced using two light bulbs
  separated by some distance.

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II. Mixing Colors By Addition

• d. Demonstrate shadows using red, green and blue
  bulbs individually and then in combinations of
  first 2 and then all three.
• e. Quiz

Colored Light Box Meter Stick - Quiz
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II. Mixing Colors By Addition

• C. Very small and closely spaced areas of color
  are perceived by the eye-brain system as the
  additive combination of the individual colors.
• 1. What Colors Make up a TV Screen? a. Freeze
  a colored video or
• b. Tape of color bars from TV
• Investigate using a lens.

TV or Computer Screen Hand Lens
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II. Mixing Colors By Addition

• Use a lens to view a comic strip up close?
• Use a lens to view colored objects close up.
  (page 426 of text)
• 4. Use a lens to view black and white pictures in
  a text and/or a newspaper.

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B
-Y
-B
Y
White
White
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B
-Y
-B
Y
White
White
Make color copies, then scan, overlap?
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II. Mixing _______ By Addition

• Different small images on a piece of paper, TV
  screen etc. when perceived by the eye-brain can
  provide very interesting results.
• 1. What happens when many small images are used
  to make a picture?
• 2. Does the image change when viewed from
  different distances? Try it.

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Say the Color, not the Word
YELLOW
BLUE
ORANGE
BLACK
RED
GREEN
PURPLE
YELLOW
RED
ORANGE
GREEN
BLACK
PURPLE
BLUE
RED
GREEN
BLUE
ORANGE
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Say the Color, not the Word

• YELLOW BLUE ORANGE
• BLACK RED GREEN
• PURPLE YELLOW RED
• ORANGE GREEN BLACK
• BLUE RED PURPLE
• GREEN BLUE ORANGE

Left Right conflict within brain Your right
brain tries to say the color but your left
brain insists on reading the word.
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III. Mixing Colors By Subtraction

• Colored lights and colored objects can be
  described in terms of three attributes hue,
  saturation and brightness.
• The Attributes of Color
• a. Hue Main Color Name
• A sensation
• Saturation Purity of Color
• Rich or pale Strong or weak
• Brightness Intensity
• A sensation

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III. Mixing Colors By Subtraction

• 2. The color of a light source is described
  using the light that enters ones eyes.
• 3. The name of a filter is determined by the
  color of light transmitted when white light is
  incident on the filter.

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III. Mixing Colors By Subtraction

• Look through red
• white ? R G B
• red ? - G - B
• b. Look through green
• white ? R G B
• green ? - R - B
• c. Look through blue
• white ? R G B
• blue ? - R - G

Color Filters
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III. Mixing Colors By Subtraction

• d. Look through red and green
• white ? R G B
• red ? - G - B
• green ? - R - B
• color seen Black
• Look through red and blue
• white ? R G B
• red ? - G - B
• blue ? - R - G
• color seen Black

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III. Mixing Colors By Subtraction

• f. Look through green and blue
• white ? R G B
• green ? - R - B
• blue ? - R - G
• color seen Black

When we say we see black what do we mean? The
black sensation is the result of no color
reaching our eyes.
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III. Mixing Colors By Subtraction

• Look through cyan
• white ? R G B
• cyan ? - R
• b. Look through magenta
• white ? R G B
• magenta ? - G
• c. Look through yellow
• white ? R G B
• yellow ? - B

Color Filters
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III. Mixing Colors By Subtraction

• d. Look through yellow and magenta
• white ? R G B
• yellow ? - B
• magenta ? - G
• color seen R
• Look through yellow and cyan
• white ? R G B
• yellow ? - B
• cyan ? - R
• color seen G

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III. Mixing Colors By Subtraction

• f. Look through magenta and cyan.
• white ? R G B
• magenta ? - G
• cyan ? - R
• color seen B
• g. Summary
• yellow and magenta
• yellow and cyan
• cyan and magenta

Red
Green
Blue
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III. Mixing Colors By Subtraction

• 2. Demonstrate what light red, green, blue,
  cyan, magenta and yellow filters transmit using
• - overhead projector
• - cardboard with slit on projector
• - grating over transmitted light
• - colored filters in 2 x 4 cards

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• Go to
• Color
• Explanation

Click Now
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III. Mixing Colors By Subtraction

• The primary colors for printing and painting
  subtraction are cyan, magenta and yellow.
• Diagram for overlapping filters
• yellow cyan

(RGB)
- B
?
(R G)
- R

G
white
- B
?
yellow
- R

green
Yellow and Cyan Filters
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III. Mixing Colors By Subtraction

• yellow magenta

(RGB)
- B
?
(R G)
- G

R
white
- B
?
yellow
- G

red
magenta cyan
(RGB)
- G
?
(R B)
- R

B
white
- G
?
magenta
- R

blue
Yellow - Magenta and Cyan Filters
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III. Mixing Colors By Subtraction

• 1. How is a colored pictures made?
• a. Three and Four Color Printing
• b. Rifle Picture
• c. Picture of Garfield

Rifle Garfield Pictures
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III. Mixing Colors By Subtraction

• D. The mixing of colored paints involves both
  additive and subtractive processes.
• Predicting the resulting color is complicated
  because it depends on the physical properties of
  paints.

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III. Mixing Colors By Subtraction

• The mixing of water colors and printer inks are
  similar to mixing color filters.
• Mixing pigment-based paints are not so simple.

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III. Mixing Colors By Subtraction

• Paint consists of tiny solid particles in a
  transparent medium.
• The particles have no color or are clear with
  dye added.
• Final result affected by
• Properties of transparent medium
• Density of the particles
• Material on which the paint is applied

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III. Mixing Colors By Subtraction

• E. The naming of the primary colors by physicists
  and artists differ.
• The physicists primary colors of light are
• red green blue
• The physicists secondary colors of light are
• magenta cyan yellow
• The artists calls its primary colors
• red blue yellow

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III. Mixing Colors By Subtraction

• IN PHYSICS
• The physicists secondary colors of light are
• magenta cyan yellow
• The artists call their primary colors
• red blue yellow
• Conclusion
• Artists say red Physicists think magenta
• Artists say blue Physicists think cyan

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III. Mixing Colors By Subtraction

• Demonstrate
• Baggie Ad Blue - Yellow ? Green
• Physicist Cyan - Yellow ? Green

Baggies Demo Baggies
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III. Mixing Colors By Subtraction

• Evaluation
• 15 Question Test

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What is the Color?

• A. The color an object appears depends on the
  color of the illuminating light and the
  properties of the object which determine what
  color reaches ones eyes.
• Shine red, green, and then blue light on the
  colored paper.

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What is the Color?

• B. The color an object appears depends on the
  color of the illuminating light,
• the properties of the object,
• and anything in the path of the light before it
  reaches ones eyes.

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Red
What will the following look like when looking
through a red, green, blue color filter?
Green
Blue
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Look through GREEN filter.
Look through RED filter.
Look through BLUE filter.
Red
red filter ? red green filter ? black blue
filter ? black
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Look through GREEN filter.
Look through RED filter.
Look through BLUE filter.
Green
red filter ? black green filter ? green
blue filter ? black
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Look through GREEN filter.
Look through RED filter.
Look through BLUE filter.
Blue
red filter ? black green filter ? black blue
filter ? blue
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Red
Green
Blue
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What is the Color?

• C. What is the color of the letters made with
  colored magic markers?
• a. Examine the letters looking first through a
  red filter, then a green filter, and finally a
  blue filter.
• Describe what you see?

Magic Marker Color Sheet
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What is the Color?

• 3. Conclusion
• The colors of the letters appear the same
  whether
• 1. looking at them through a colored filter or
• 2. looking at them illuminated by a similar
  color light without using a color filter.

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• What is the Color?

• Using overhead, illuminate the following objects
  with
• Red Green Blue
• light.

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• What is the Color?

• Illuminate objects with
• red, green, blue light.

• Red and White Card Cloth
• Red-White-Blue Cloth
• Multi-Colored Cloths
• Painted Color Swaths
• Dusters T-Shirts
• Lab Coat

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Look at the dusters through a red filter.
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Look at the dusters through a green filter.
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Look at the dusters through a blue filter.
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V. Are You Color Blind?
Click Here
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V. Evaluation

• 1. What are the colors of the letters?

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• Thats all folks!

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