What do colorblind people actually see ?

Colorblindness is a disorder of the cones in the retina of the eye that causes the affected person to have difficulty in distinguishing colors. It can vary in type and severity.

Red-green colorblindness is inherited by X- linked recessive mechanism and is thus found in males. It is very very rare in females.

Are you color blind ?
Find out here :

http://www.archimedes-lab.org/colorblindnesstest.html

http://enchroma.com/test/

http://colormax.org/colorblind-test.htm

http://www.colormax.org/

What does a color blind person actually see ?
Let me show you, in pictures.

If you have a friend who is colorblind, show them these photos - and ask them what the difference between the pictures is !

Flowers - Normal vision

Flowers - Protanopia

Flowers - Deuteranopia

Flowers - Tritanopia

The above images show what a normal person sees vs what a color blind person sees. If you ask a colorblind person what the difference in color between the pictures is, they may not be able to make out any difference.

Here are a few more examples to show the difference  - colorpencils, traffic lights, 

Pencils - Normal Vision

Pencils - Deuteranopia

Pencils - Protanopia

Pencils -Tritanopia

Traffic lights

Street lights - Normal vision

Street lights - colorblind

Color vision test as seen by color blind person

First circle - person with normal vision sees 2. The other two circles show what a colorblind person sees

Here is another colorblindess simulator based on flash :

http://www.webexhibits.org/causesofcolor/2.html

You can also upload your own photos and see what they would look like to a colorblind person here : (Server seems to be down today)

http://www.vischeck.com/vischeck/vischeckImage.php

This particular site is supposed to check a website to see what it would look like to a colorblind person. Especially important for a website, blog or any resource aimed at being accessible to colorblind people.

Another software called Daltonize is supposed to recolor images so that colorblind people can make out the difference.

Here is a Chrome browser plugin for ColorBlind users :https://chrome.google.com/webstore/detail/chrome-daltonize/efeladnkafmoofnbagdbfaieabmejfcf?hl=en

The developers website : http://www.daltonize.org/2010/05/chrome-daltonize-color-accessibility-in_13.html

Another solution for colorblind people is special filter glasses like enChroma glasses.

More about that in a later post.

Here's a comedy sketch of what a colorblind person gets asked.

Sim Daltonism is a FREE color blindness simulator for Mac OS X. It filters in real-time the area around the mouse pointer and displays the result — as seen by a color blind person — in a floating palette.
Since there are many types of color blindness, Sim Daltonism allow you to choose the one you want to see. Available filters are:

• Monochromacy (complete)
• Monochromacy (partial)
• Protanopia (complete red-green)
• Protanomaly (partial red-green)
• Deuteranopia (complete red-green)
• Deuteranomaly (partial red-green)
• Tritanopia (complete blue-yellow)
• Tritanomaly (partial blue-yellow)

Visolve is a FREE software tool that transforms colors of the computer display into the discriminable colors for various people including people with color vision deficiency, commonly called color blindness. In addition to the color conversion, it also has color filtering and hatching capabilities.

Visolve making an invisible image visible

Vissolve also has a page to try out their algorithm on an image that you upload so that you can check if it will work for you.
Or you could use it to find what is written on colorblind invisible images like this one :

What do you see ?

Can you read anything here ?