Color blindness is a major factor in accessibility related to web design, because it involves the inability to distinguish information. This is caused by the visually impaired seeing similar shades of certain colors instead of the contrasting colors which were intended for the website. Over 10 million people in the United States alone have this condition. There are different kinds of colorblindness and even total colorblindness, which involves having vision on a grayscale.

To the right, there is a picture of several color blindness tests put together. If someone can't see the number in one of the squares, they are most likely color-blind in some way.

There are three major kinds of color blindness:

* Deuteranopia, is an insensitivity to green.
* Protanopia, is an insensitivity to red.
* Tritanopia, is an insensitivity to blue.

Since we know what color blindness is, we are able to create websites which use colors that are distinguishable to almost all people affected by this disability. There are also several tools which can change style sheets to allow for more contrast on a web page, providing those with color blindness close to the same web accessibility and usability as those with full vision.

Contrast is Everything – Contrast is a measure of how well colors can be distinguished from others. When making a website, contrasting colors should always be used, but especially for the color-blind, colors must be chosen that color-blind people are rarely affected by. This way, people with color blindness and normal vision can all tell the difference in the color scheme.

Graphics Must Contrast – All graphics on a website should have contrasting colors, but also make sure that graphics are used which do not contain a lot of red, green and blue together. This will ensure color-blind people can also see the images on a website.

Check Elements – When you are creating elements of your website, such as tables, make sure the order is logical. By doing this, you will allow the screen reader to make sense when it reads the information off to a blind person.

Watch Page Length – For any website, pages should not be too long. People get bored too easily, but especially for the visually impaired, pages should be made as short and concise as possible. If there are long pages, punctuate them with headings. This way, the various sections are identified easily.

HTML Validation – You should always validate your code. This will stop screen readers and other alternate browsers from misinterpreting the source code. A Doctype identifies how you validate your code. Always make sure you have the right Doctype for the html page you are designing.

 

 

Alt & Title Tags – Using alt and title tags for images and other elements are very helpful for the visually impaired since screen readers use the descriptive text to tell them what they cannot see. Also, be sure to use fairly long descriptions for complex images.

 

 

Color Links Correctly –Many people forget the background and font colors included for links when they have not been used, are hovered over, or have been used. Always pay attention to these colors, and again, check the contrast.

 

 

Add Links for Pictures – Many software programs used by the visually impaired do not read image maps, so it is important to make text links available in your content also.