COLOR  PHENOMENA Page: 05. 03
Introduction Ingredients Spectra Attributes The Human Eye Color Mixing General Terms
Color Spaces How to measure Color Scales Color Effects After Images Contents

The Human Eye

HUMAN EYE on page 05.00
SENSITIVITY on page 05.01
WHITENESS on page 05.02
COLOR-BLINDNESS on this page

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COLOR-BLINDNESS

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 A bull is completely Color-Blind. It becomes aggressive because of a motion of an object.

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Color-Blindness more correctly called color vision deficiency, describes a number of problems in identifying various colors and shades. 
Total Color-Blindness (seeing in only shades of gray) is extremely rare.
Unfortunately, there is no cure for hereditary color vision deficiency. 
People can try to develop their own system or be taught to recognize colors by other means. 
Specially tinted eyeglasses may help someone with color vision deficiency. 

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blue-violet green red
 


Color-Blindness is the inability to distinguish one or more of the  primary colors. 
There are three kinds of light-sensitive cones in the layer of tissue lines in the back of the eyeball. 
One type absorbs light in the wavelengths of blue-violet and another in the wavelengths of green. 
The third type is most sensitive to wavelengths of red but is also sensitive to yellow.

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Color-blind persons may be blind to one, two or all of the three colors.
Blindness to blue is called tritanopia, to green: deuteranopia and to red: protanopia.
A blue-blind person cannot distinguish between blue and yellow.
Green-blind persons are unable to see the green part of the visible spectrum
Red-blind persons are ordinarily unable to distinguish between red and green.

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Color-Blindness is caused by a defect in the retina or in other nerve portions of the eye.
Total Color-Blindness in which all hues are perceived as variations of gray, is know as Monochromatic.
This condition is a congenital defect, extremely rare, and affects men and women almost equally.

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Partial Color-Blindness, called Dichromatism, consists generally of the inability to differentiate between the reds and the greens
or to perceive either reds or greens; infrequently, the confusion may involve the blues or the yellows.
Dichromatism is the most common form of Color-Blindness, affecting about 10 percent of men and about 0.2 percent of women.
Many victims of the defect are unaware that they are Color-blind.

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Color vision deficiency (also known as: color blindness) is a condition in which the eye cannot distinguish specific colors.
This is a condition which is mostly inherited.
The most common version of color blindness, about 99%, is the red/green deficiency.
This blindness makes it difficult distinguishing red and green. 
Another version, though very rare, is the blue/yellow deficiency.
Unfortunately, for this deficiency there are no tests available.

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Several color blindness studies show different outcomes, but on average: 10 % of the male and 0.2 % of the female European population are suffering from color blindness.
For other populations, there are no figures to be found.
A total color blindness (hence, only seeing shades of grey) is extremely rare.

 

 
The spectrum as perceived by individuals with normal color vision, protanopia, deuteranopia and tritanopia

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05-03-01

NORMAL


05-03-05

05-03-02

PROTAN


05-03-06

05-03-03

DEUTERAN


05-03-07

05-03-04

TRITAN


05-03-08

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Some colors as perceived by individuals with normal color vision, protanopia, deuteranopia and tritanopia

 

NORMAL

PROTAN

DEUTERAN

TRITAN

RED

       
YELLOW        
GREEN        
CYAN        
BLUE        
MAGENTA    

 

 
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The images below are a part of the test for Color-Blindness

by Dr. Shinobu Ishihara


05-03-09

Left and Right Image

Both normal and those with all color vision 
deficiencies should read the numbers 12 and 25.

These images are only made for tracing simulators.


05-03-10


05-03-11

The normal read the figure for 2 and the color-blind can hardly read it.


05-03-12

Left and Right Image

Individuals with normal color vision will see the number 3.
Those with the Red-Green deficiencies will see the number 5.
Total color blindness should not be able to read any numeral.


05-03-13


05-03-14

 Left Image
The normal read the figure for 5.
The color-blind can hardly read it or will read incorrectly.

Right Image 
The normal read the figure for 5.
The Red-Green-blind will see the number 2. 
The  total-color-blind can hardly read it.

My question: Try to copy the right image and paste it for instance in MS-Word. 
Then click on the image and enlarge with the mouse.

05-03-15-resized
At a certain (smaller) size a non-colorblind person can also see the digit 2.
Who can give an explanation for this?

An answer from Lyndon Hill from the UK.
The reason why the smaller colour dot image is visible to colour blind people is do with aliasing.
When you resize an image you resample it.
Look up "sampling theorem"and Nyquist-frequency in a signal processing book.

 

 

 

 


05-03-15


05-03-16

Left Image
The normal read the figure for 5.
The color-blind can hardly read it.

Right Image
Normal color vision and those with total color blindness should not able to read any number.
The majority of those with Red-Green deficiencies should read the number 5.


05-03-17


05-03-18

Normal color vision should read the number 6.
The majority of those with color vision deficiencies cannot read this number or will read it incorrectly.


05-03-19

Normal color vision should read the number 7.
Those with color vision deficiencies should not be 
able to read this number or will read incorrectly.


05-03-20

Those with normal color vision should read the number 8. 
Those with red-green color vision deficiencies should read the number 3. 
Total color blindness should not be able to read any numeral.


05-03-21

Individuals with normal-color-vision will see the number 15.
Those with the Red-Green deficiencies will see the number 17.
The  total-color-blind can hardly read it.


05-03-22

Normal color vision should read the number 26.
In protanopia and strong protanomalia the number 6 is read.
In mild protanomalia both numerals are read but number 6 is clearer than number 2.
In deataranopia and strong deuteranomalia only the number 2 is read.
In mild deuteranomalia both but the number 2 is clearer than number 6.


05-03-23



Normal color vision should read the number 29. 
Those with Red-Green deficiencies should read the number 70.
The  total color blind can hardly read it.

 


05-03-25

Normal color vision should read the number 42.
In protanopia and strong protanomalia the number 2 is read.
In mild protanomalia both numerals are read but number 2 is clearer than number 4.
In deataranopia and strong deuteranomalia only the number 4 is read.
In mild deuteranomalia both but the number 4 is clearer than number 2.


05-03-26

Individuals with normal-color-vision will see the number 45.
The color-blind can hardly read it.


05-03-28

Individuals with normal color vision will see the number 56.
The color-blind can hardly read it.


05-03-29

Individuals with normal -color vision will see the number 74.
Those with the Red-Green deficiencies will see the number 21.
The  total color blind can hardly read it.


05-03-30

Individuals with normal-color-vision will see the numbers 97.
The  color-blind can hardly read them.














05-03-31

The normal should trace along the purple and red lines between the two X's.
In protanopia and strong protanomalia only the purple line is traced.
In mild protanomalia both lines can be traced but the purple line is easier to follow.
In deataranopia and strong deuteranomalia only the red line is traced.
In mild deuteranomalia both lines are traced but the red line is easier to follow.


05-03-32

Normal will trace the Orange line between the two X's.
The majority of those with color vision deficiencies will be unable to follow the line
 or will follow a line different to the normal one.


05-03-33

Those with normal color vision will trace the Blue-Green line between the two X's.
The majority of those with color vision deficiencies will be unable to follow the line
 or will follow a line different to the normal one.


05-03-34

Normal should trace the line connecting the Blue-Green and the Yellow-Green.
Those with Red-Green deficiencies trace the line connecting the Blue-Green and the Purple.
Those with total color blindness cannot trace any line.


05-03-35

 Normal color vision should trace the line connecting the purple and the orange between the two X's.
Red-Green deficiencies should trace the line connecting the Purple and the Blue-Green.
Total color blindness and weakness cannot trace any line.


05-03-36

Both normal and those with color deficiencies can trace the winding line between the two X's.

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Color-Blindness which affects about 60 times as many males as females is a sex-linked recessive characteristic.
A woman must inherit the trait from both parents to be color-blind.
A color-blind man and a woman of normal color vision have daughters who have normal vision but are carriers of the trait.
These daughters may have color-blind sons and daughters who are carriers.
The son of a man of normal color vision and a carrier woman may be color-blind and the daughter of such a union may be a carrier of the trait.

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Normal Father Carrier Mother
chromosome Y chromosome X chromosome X chromosome X
Normal Son Affected Son Normal Daughter Carrier Daughter
Y X Y X X X X X
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2010-05-18

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Red-Green color-blindness:
A form of color-blindness in which red and green are perceived as identical.
This is the most common type of color-blindness.
It is inherited in an X-linked recessive manner and affects 6% of males.
It is also known as deutan color-blindness, deuteranopia, and Daltonism.

 

 


05-03-37

Wald, George
b. Nov. 18, 1906, New York, N.Y., U.S.
d. April 12, 1997, Cambridge, Mass.
American biochemist who received (with Haldan K. Hartline of the United States and Ragnar Granit of Sweden)
the Nobel Prize for Physiology or Medicine in 1967 for his work on the chemistry of vision.


05-03-38

Dalton, John
b. Sept. 6, 1766, Eaglesfield, Cumberland, Eng.
d. July 27, 1844, Manchester
British chemist and physicist who developed the atomic theory of matter and hence is known as one of the fathers of modern physical science.