Light and color

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					    Light
     and
    color
    examples of
perception problems
    While we can all “see”
• Our ability to perceive color is a very
  individual characteristic
• Apparently our eyes work the same
  way,
  but just as some people have
  differing athletic abilities,
  we also have differing perceptual
  abilities
This presentation illustrates some of
  these differences.
       In the first set of slides
• The intersections of the white lines are
  completely clear,

• But many people perceive “spots” in the
  intersections away from where the are
  focused.
• This effect may be stronger or weaker,
  depending on the background color
   In the next set of slides
• Some people perceive the pattern to
  be rotating
• Yet the circles are not moving . . .

• Again, the intensity of the
  perception may depend on the
  background color
    The next set of slides illustrate the
 manner in which the rods assist our vision
Instructions :
• Stare at the black spot in the center of the slide
• Be aware that you can read the other letters even
  while looking only at the center letter.
• Then shift you focus to a letter in the first ring
• Be aware that the center spot is fuzzy, but the
  other, outer, larger letters are still in focus
• Now shift your focus to a letter in the 2nd ring
• Be aware that the smaller letters are now hard to
  identify while the outer letters are still clear
• Repeat these steps until you reach the outer ring.
                            W
    D                       Q                       T
        F                                       B
                            H
                R                       O
                            G
                        N       A

U   K       Z       Q

                        S       T
                                    M       Y       L   P
                            W

                V                       J
                            G
        M                                       P
    B                       A                       Y
                            C
Again, color of background
  seems to change the
 effects for some people
                        W
    D                   Q                       T
        F                                   B
                        H
                R               O
                        G
                    N       A


U   K       Z   Q

                            T
                                M       Y       L   P
                    S
                        W
                V                   J
                        G
        M                                   P
    B                   A                       Y
                        C
                        W
    D                   Q                       T
        F                                   B
                        H
                R               O
                        G
                    N       A


U   K       Z   Q

                            T
                                M       Y       L   P
                    S
                        W
                V                   J
                        G
        M                                   P
    B                   A                       Y
                        C
                        W
    D                   Q                       T
        F                                   B
                        H
                R               O
                        G
                    N       A


U   K       Z   Q

                            T
                                M       Y       L   P
                    S
                        W
                V                   J
                        G
        M                                   P
    B                   A                       Y
                        C
        The accumulative effect
    of these individual differences

• Has a pronounced effect on our
  ability to read material.

• Be aware of differences in your
  reading ability based on the
  background colors, even though you
  are already familiar with the text.
Procedure:

1. Practice releasing the steel from the top of the
launching ramp. Develop a method that produces a
consistent release. Se sure to catch the steely and not
allow it to strike the backstop while practicing.
2. Once you have developed a consistent release
method align the backstop with the right most vertical
line.
3. Gently tighten the backstop to prevent if from
moving.
4. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.
5. Align the backstop with the next vertical line to the
left.
6. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.

Continue this procedure until 3 marks have been made at
each of the vertical line positions.
Procedure:

1. Practice releasing the steel from the top of the
launching ramp. Develop a method that produces a
consistent release. Se sure to catch the steely and not
allow it to strike the backstop while practicing.
2. Once you have developed a consistent release
method align the backstop with the right most vertical
line.
3. Gently tighten the backstop to prevent if from
moving.
4. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.
5. Align the backstop with the next vertical line to the
left.
6. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.

Continue this procedure until 3 marks have been made at
each of the vertical line positions.
Procedure:

1. Practice releasing the steel from the top of the
launching ramp. Develop a method that produces a
consistent release. Se sure to catch the steely and not
allow it to strike the backstop while practicing.
2. Once you have developed a consistent release
method align the backstop with the right most vertical
line.
3. Gently tighten the backstop to prevent if from
moving.
4. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.
5. Align the backstop with the next vertical line to the
left.
6. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.

Continue this procedure until 3 marks have been made at
each of the vertical line positions.
Procedure:

1. Practice releasing the steel from the top of the
launching ramp. Develop a method that produces a
consistent release. Se sure to catch the steely and not
allow it to strike the backstop while practicing.
2. Once you have developed a consistent release
method align the backstop with the right most vertical
line.
3. Gently tighten the backstop to prevent if from
moving.
4. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.
5. Align the backstop with the next vertical line to the
left.
6. Release the steely 3 times from the top of the
launching ramp. Each time will produce a mark on the
backside of the marking paper.

Continue this procedure until 3 marks have been made at
each of the vertical line positions.
These examples illustrate differences
         in reading ability
are caused by other unrecognized
  factors that are not normally
  associated with reading ability.

Providing appropriate lighting (color)
 is a critical aspect of establishing a
 good reading environment for many
 people.
Other examples of reading difficulties
  associated with color perception
This is easy to read, so you can
decide to ignore it very rapidly
Very low contrast text is read by the
part of the brain which locates
objects, the “where” system.
As long as the words are easy to
recognize, you can read rather
rapidly, but recondite or
infrequently encountered words
seem unfamiliar and have to be
read letter-by-letter.
This is also hard to read. It jumps
around and seems unstable
because the “where” system has
trouble seeing it. Advertisers use
this trick to make you pay
attention because you have to
slow down and read each
individual word.
This is also hard to read. It jumps
around and seems unstable
because the “where” system has
trouble seeing it. Advertisers use
this trick to make you pay
attention because you have to
slow down and read each
individual word.
 Changing the color of the letters
           helps a lot
This is also hard to read. It jumps
around and seems unstable
because the “where” system has
trouble seeing it. Advertisers use
this trick to make you pay
attention because you have to
slow down and read each
individual word.

Changing the background color also
            helps a lot
This is hard to read even
though each individual letter
is easy to see, so you have
to pay a lot of attention in
order to read it.
             Final example
• Retinal fatigue . . .
     Causes an apparent “saturation” in the
  signal being sent to the brain along the
  optic nerve

• When a different “background noise level”
  is presented, the persistence of the
  saturation signal creates an “illusion”, an
  image that exists in the brain but not in
  reality . . . .

				
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posted:6/23/2012
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