A Quick Introduction to Colorblindness
-
Upload
angel-blood -
Category
Documents
-
view
215 -
download
0
Transcript of A Quick Introduction to Colorblindness
-
7/28/2019 A Quick Introduction to Colorblindness
1/7
A quick introduction to colorblindness
About 8% of the male population has some form of colorblindness. In this article well
take a look at the basics of how colorblindness works.
Posted on10 Jan, 2012
TypeArticle
Categoriessticky
Theoretics
Share
To see anything at all we need some tiny little helpers inside our
eyeballs, the so called photoreceptors. There are two different types
of them: rods and cones. Both of them are sitting on the retina at the
back of your eye and pass information on to our brain. The rods are
sensitive to light while the cones pick up color.
Each of the cones is carrying one out one of three different
photopigments red, green and blue and reacts differently on
colored light sources. For each of this three types there exists a
specific color absorption curve with peaks at different points in the
color spectrum.
http://wearecolorblind.com/examples/category/stickyhttp://wearecolorblind.com/examples/category/stickyhttp://wearecolorblind.com/examples/category/theoreticshttp://wearecolorblind.com/examples/category/theoreticshttp://wearecolorblind.com/examples/category/theoreticshttp://wearecolorblind.com/examples/category/sticky -
7/28/2019 A Quick Introduction to Colorblindness
2/7
Mixing together the information of those three different types of
cones makes up our color vision.
Now, when one type of cones malfunctiones the color this cone
would normally absorb is altered. This changes the color perception,
resulting in a (somewhat) different way of perceiving color. This is
what we call colorblindness.
-
7/28/2019 A Quick Introduction to Colorblindness
3/7
Types of colorblindness
The tree types of cones translate into tree main types of
colorblindness:Deuteran (green),Protan (red) and Tritan (blue).
In each of these cases, the affected cones can either be mutated or
defective. A mutated cone causes a slight shift and a defective cone
causes bigger shift in the color perception. This results in a total of
six types possible types of colorblindness.
The Deuteran (green) and Protan (red) inefficiencies are the most
common ones:
Deuteranomaly: malfunctioning green cone (common)
Deuteranopia: missing green cone (rare)
Protanomaly: malfunctioning red cone (rare)
Protanopia: missing red cone (rare)
-
7/28/2019 A Quick Introduction to Colorblindness
4/7
Blue-type colorblindness is also possible, but very rare:
Tritanopia: missing blue cone (very rare)
Tritanomaly: malfunctioning blue cone (very rare)
Its a male problem
About 8% to 10% of the male population is colorblind.
Colorblindness is most present in males due to the way genetics
work (see footnotes). Only an estimated 0.5% of the female
population is colorblind. Tritan-type colorblindness is not gender
specific, women and men are equally affected.
Type Prevalence
Deuteranomaly (green) 4.63%
Deuteranopia (green) 1.27%
Protanomaly (red) 1.08%
-
7/28/2019 A Quick Introduction to Colorblindness
5/7
Type Prevalence
Protanopia (red) 1.01%
Tritanomaly (blue) 0.02%
Tritanopia (blue) 0.03%
Its not all black and white
There are many people who think the colorblind cant see any color.
But the term is misleading, more than 99% of all colorblind people
can see color.As you can see, people with the two most common types of
colorblindness Deuteran (green) and Protan (red) dont really
suffer a radical change in the way they see color.
However, they do have limited ability to distinguish between reds
and greens (and any other color that has their missing color in it),
especially in shades of a certain color. Something might look green,
but in certain situations it could also look red or blue.
The red and green cones lie quite close to each other in what colors
they perceive (see the graphs above). They intersect at various
points; when the green cones dont work, the red ones still pick up
some green and the other way around.
The greens might not be as green as a non-colorblind person would
perceive it, but its still within the category we would call green.
The Tritant (blue) colorblind have the blue end of the spectrum
missing or altered. There is very little intersection between the other
cones, this explains the big change in color perception.
The following table lists some of the most problematic colors for
each main type of colorblindness:
Type Problematic colors
-
7/28/2019 A Quick Introduction to Colorblindness
6/7
Type Problematic colors
Deuteran (green)
Green/red, green/blue, green/gray,
green/brown, blue/purple, orange/red,yellow/orange.
Protan (red)purple/dark blue, orange/green,brown/dark green, red/brown,
green/yellow, gray/purple
Tritan (blue)blue/yellow, violet/yellow-green, red/red-
purple, dark blue/black, yellow/white
In conclusion
All of this might sound very medical and confusing, but the basics
are very simple;
The colorblind have a narrowed color perception.
Green is still green and red stays red most of the
time, but not as vibrant or bright as a non colorblind
would see it. Colors lie closer to each other, especially
shades of colors.
In the next articles Ill explain how these basics of colorblindness
translate into practical difficulties, common frustrations and
(usually) easy solutions.
Footnotes
The two common types of colorblindness (red-green and green-red)
are the types of colorblindness that will be most discussed on this
site. There are various other types of colorblindness with different
perceptions, mutations and causes; they are however quite rare.
-
7/28/2019 A Quick Introduction to Colorblindness
7/7
So as not to confuse the message with different clauses or oddities I
wont focus too much on these other rare types in general examples
or articles. However, in the end any given solution or analysis will
also work for these types of colorblindness.
Much of the information above is based on and used with
permission from the most excellentcolblindor.comby Daniel Fluck.
More information on the working of colorblindness can be found in
theColorblind Essentials series.
For more information about the genetics side of colorblindness, take
a look atthis article on colblindor.com
http://www.colblindor.com/http://www.colblindor.com/http://www.colblindor.com/http://www.colblindor.com/2010/02/23/color-blind-essentials/http://www.colblindor.com/2010/02/23/color-blind-essentials/http://www.colblindor.com/2010/02/23/color-blind-essentials/http://www.colblindor.com/2006/03/07/the-biology-behind/http://www.colblindor.com/2006/03/07/the-biology-behind/http://www.colblindor.com/2006/03/07/the-biology-behind/http://www.colblindor.com/2006/03/07/the-biology-behind/http://www.colblindor.com/2010/02/23/color-blind-essentials/http://www.colblindor.com/