44

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).

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    +1, I'm not even colorblind and I have a hard time making out the links on the main site after the latest redesign! – Paul Gessler Jul 3 '16 at 21:54
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    Almost all modern browsers load a user .css which you can use to change the color of links. See e.g. superuser.com/questions/638250/… – Ulrike Fischer Jul 4 '16 at 8:37
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    Thanks, that is useful, but I think still not ideal: no single color will work as a link color in all environments (both as far as being distinguishable from normal text, as well as aesthetically felicitous in context). Something like 5% of the population is colorblind; good UX designers should make sites that are usable for those people, too. – Simon C Jul 4 '16 at 14:21
  • Here is another option under Chrome - an extension: How can I change the default visited links color in Chrome? Is there an easy way to make it happen? – Werner Jul 4 '16 at 17:37
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    @SimonC In addition to Ulrike's idea, there's CSS key text-decoration:underline which adds underlining. – yo' Jul 4 '16 at 20:35
  • Similar to Ulrike's comment, I posted a CSS solution to change the link colors using the Stylish extension available for Firefox or Chrome. You could modify the code there to change the link color to your liking – Null Jul 7 '16 at 18:34
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    With CSS - eg. using stylish - you can also do other things than just color. For example you could underline links (which used to be common), put a line both over and under the link, put a line through the link, or even make box around the link (and perhaps make it look like a button). I myself used to "reset" the link-color to blue (unvisited), magenta (visited), red (active - ie. pressed) and green (hover over) - as well as adding a box around all "link-images" with the same color. This way I could easily see which links I'd visited before. – Baard Kopperud Jul 9 '16 at 13:11
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  • consider using browsers through console. Black background, as psoft suggests, can be a rest for all eyes, color blind or not. two console browsers i've used and recommend: 1. w3m. 2.lynx. just type in a terminal: [chosen-browser-name whatever-link.com] and you're there. – nilon Jul 13 '16 at 3:19
  • Just curious: how does red-green colourblindness affect one's ability to distinguish colour from greyscale? I thought it only affected the ability to distinguish signals from red and green cones. – Myridium Jul 17 '16 at 8:01
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    Perhaps the article and resources at rigdenage.co.uk/safecolours/index.html would be useful to the site designers. – cfr Jul 18 '16 at 0:11
13

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.

7

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:

  • 2
    good suggestions, but, pray, how to activate the "item" format in a comment? (the form with full title does work in that context, and it's what i try to use, if there's enough space.) – barbara beeton Jul 8 '16 at 20:02
  • @barbarabeeton Well yes, this doesn't work in comments for sure. Not much we can do about that. I guess in a comment you could say you can find more information here: • Colorblind, links hard to see – Alan Munn Jul 8 '16 at 20:04
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    In my experience, the "here"/"this" kind of links are among the easiest to get a lock on; you know there is a link, and you know exactly where to click for it. You might find them annoying for other reasons (I don't), but this is I think independent of the issue noted in the OP. – Simon C Jul 8 '16 at 20:23
  • @simon That's interesting to hear. So in my second version, you will tend to click on the "here" and be disappointed, effectively? Does that also apply to the bullet method too? – Alan Munn Jul 8 '16 at 20:29
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    @Alan No, I reckon I'd be ok with all those options, actually. Probably my eyeballs scan ahead a bit faster than my click-finger. – Simon C Jul 9 '16 at 0:00
  • Remember the good ol' days - around 1995 - when (almost) every single link where of the form "blah blah blah blah here.", "blah blah click here.", and "blah blah my email address is here."... And of course a terrible, swirly, very colorful background-image which made the text unreadable, and lots and lots of animated GIFs! – Baard Kopperud Jul 9 '16 at 13:17
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    How about bringing everybody's favourite marquee back? /ducks – Paulo Cereda Jul 10 '16 at 1:53
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    Personally, i am very very confused by leaving a link here, cause it obvously takes me to another place, which is not here. – Johannes_B Jul 10 '16 at 14:11
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    This is not a scalable solution, and requires too many people to care. It also does not work for thousands of old posts. – Raphael Jul 12 '16 at 13:54
0

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.

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    although red/green is the most frequent type of colorblindness, i have an acquaintance who suffers from the yellow/blue variety. that makes it nearly impossible for him to comprehend many slide presentations. so i don't think using a yellow background would by itself be much of an improvement. also, i'm not sure how much control the tex moderators have over such decisions -- they seem to be made at a higher level. however, this is a real problem and should be considered whenever a site makeover is undertaken. – barbara beeton Jul 8 '16 at 0:05
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    If a color that is not implicated in colorbindness can be implemented, it should be, as quickly as possible. – A Feldman Jul 10 '16 at 14:05
0

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.

Electromagnetic Spectrum Comparison

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.

  • 1
    What's the graphic got anything to do with your discussion? I don't see how anyone at SE would use shapes for generic links INSTEAD of colours... they may use it IN ADDITION TO colour (like what is done on Wikipedia for external links). – Werner Jul 8 '16 at 6:32
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    The question about TeX - LaTeX, not about TeX or generic web pages. When saying "Link Color In TeX and the WWW", are you referring to TeX.SE and (all) other websites? Doesn't that just refer to all websites? Moreover, there doesn't seem to be much value in saying "some people opt for blue hyperlinks, which affect blue... colourblindness". It seems obvious or superfluous, don't you think – Werner Jul 8 '16 at 6:36
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    The answer seems to elaborate on TeX-documents compiled into a final pdf and the colours therein. But i fail to see how the answer adresses the question of How to better display links on TeX.SX. – Johannes_B Jul 8 '16 at 9:16

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