5% of males are red-green colorblind. Never mix red and green. If you do 2.5% of your audience have just stopped using your product/looking at your presentation.
Red-green was in the context of mixing colors, not color-blindness here. If you e.g. mix oil/tempera colors, red and green give you a really ugly grey color; on the edges between red and green patches you'd get something similar.
I have the opposite issue - my color perception is 100%, so I can distinguish very slight differences in color tones. What might look acceptable to you might be unacceptable to me and vice versa ;-)
As a red-green colourblind male. I'd temper that statement to don't mix red and green for encoding information. Ideally don't use colour as the sole means of encoding information anywhere.
The experience of colourblind people can vary wildly but for me other colours are harder to discern than red vs green. Blues, purples and pinks all are all very tricky.
If however you want to use red and green for some styling element, knock yourself out!
Exactly, I'm also slightly red-green colorblind, but I have only really have difficulty with green and yellow when I need to differentiate them quickly.
> purely design and doesn't serve a functional purpose it would be fine
Or if it does provide functional information (traffic-light style status displays for instance), it is fine if the information is also carried by other means.
> do it in Black and White first ... then add colors.
Exactly. That way anyone with reasonable vision[1] can use the result and it is enhanced for those with good colour vision, rather than requiring good colour vision to be properly usable.
[1] Other serious visual impairments (up to and including complete blindness) should be considered too where possible, of course. Keep contrast high, try to design with screen readers and other common aids in mind, ...
For Screen Readers I've found it helpful to use elinks or lynx to develop the initial HTML.
If your application remains readable and functional on a terminal output, chances are high a screen reader can handle it (since I can't afford any of the screen readers people seem to use, that's what I'm stuck with, aside from following general guidelines on this)
Progressive enhancing, the process of having a working HTML page, enhance with CSS/Images and then enhance with JS, is sadly a rather lost art in modern webdevs.
It is pretty binary. If I can't understand your slides because you have one set of points in red and the other in green I walk away and ignore your presentation.
Colorblindness also has very well established definitions. Note: learning what words mean should come before trying to redefine them.
Those definitions are mostly wrong. On HN (my experience) people associate colorblindness with and only with "red-green color blindness". This is obviously wrong, or at least not well defined.
It's not binary. There is a range from not colorblind to minor defience to fully red-green colorblind
I have the opposite issue - my color perception is 100%, so I can distinguish very slight differences in color tones. What might look acceptable to you might be unacceptable to me and vice versa ;-)