Colorblind, links hard to see

Question

I have red-green colorblindness. I don't really notice it, except on two occasions:

• When I see an Ishihara plate.
• When hyperlinks are styled using only a color that normal people have no trouble distinguishing from non-hyperlinked text, but which I do.

For an example of what I mean, see any TeX.SX post with a hyperlink (here's one of my own). For another example, see Talking Points Memo.

This isn't the biggest deal in the world, but it can be rather frustrating. Sometimes it is clear from the context where a hyperlink is, and all is well. Sometimes it is clear that there is a hyperlink, but unclear where it is; this requires a bit of searching. Sometimes none of this is true, and I have to hover over nearly every bit of text groping for possible links; that's annoying.

There are a couple ways this might be addressed. Different color schemes could be used, but there are other kinds of colorblindness that would need to be kept in mind, and so this solution is not very robust. Even better, some other kind of formatting could be added to links (e.g., underlining), or the link color could have a different intrinsic brightness from the main text (so even the totally colorblind could make out where the links were; I believe the TeX.SX Meta links are like this).

Answer 1

I don't think it's reasonable to expect every poster to specially mark hyperlinks. There are two ways out of the problem.

1. Ask the designers to choose a color palette (or other highlighting elements) that makes the site accessible to individuals with color perception issues.

2. Hack the web yourself, e.g. with Firefox addon Stylish.

   For instance, the following simple script gives you very clear indicators of where links are:

   a:before {
     content: "[";
   }
   
   a:after {
     content: "]";
   }
   

   Or this:

   a {
     border: black solid 2pt;
   }
   

   The possibilities are (almost) endless; pick whatever you prefer.

   You can apply it to some sites, or to the whole web.

Answer 2

Here are two things that all of us can do fairly easily that might help.

• Avoid inline links wherever possible. This is especially true of links to non-contentful word like "this" or "here" which are annoying IMO even to people who can see they are links.
• Make links explicit by using a list mark-up and explain that they are links in the accompanying text.

It takes very little time to do this, and will generally make answers more readable for everyone anyway.

Here are some examples (I've made all links just link to this question).

Instead of saying:

You can find an answer to this second question here.

Say:

You can find an answer to this second question here: Colorblind, links hard to see.

Or even more explicitly:

You can find an answer to this second question here:

• Colorblind, links hard to see

Answer 3

I would suggest the use of more of the options available when answering such as

blockquoting

and preformatting.
Too much coloring of answers and comments (I have yet to see this on SE sites) can be a real nuisance. But, this is why developers use CSS to improve their GUIs and UIs to make their software colorblind-friendly. I highly suggest that Tex improve their blockquoting background color for improved visibility. Math utilizes a yellow background for blockquoting.

Answer 4

I intend to provide a comprehensive, scientifically-backed discussion of possible steps, a TeX document creator could implement to create more user-friendly TeX Documents, websites, software, etc.

Potential Problems with TeX and WWW Conventions

1. Link Color In TeX and the WWW, links are generally in blue. Some avoid red as color for emphasis text and elect for blue; however, this affects those with blue-yellow colorblindness.
2. Quantity of colors available Only so many colors can be used on a TeX document and WWW before it starts too look unprofessional. This, obviously, affects readers with colorblindness.

Okabe and Ito have developed a Color Universal Design, where they offer the following guidelines, which will help TeX Doc creators.

1. Avoid the following colors: red, yellow, green, and orange.
2. Use shapes instead of colors to distinguish types/classes of information.
3. Specify colors when defining color-based terminology in documentation.

Hope Stack Exchange and TeX document creators keep this in mind when designing/creating next time. @Simon C, please accept my answer if this helped.