On 17/12/19 5:19 am, Chris Angelico wrote:
On Tue, Dec 17, 2019 at 3:16 AM duncan smith <duncan@invalid.invalid> wrote:
Hello,
Not really specific to Python or matplotlib (but that's what I'm
using). I'm looking for a good combination of colours and symbols for
scatter plots, and combination of colours and line styles for line
plots. Too often I find myself producing these when I don't know whether
they will end up being printed in colour or greyscale. It would be a lot
easier if I could produce decent plots that would work well in either
case. I can find various stuff on colour palettes, but pretty much
nothing on symbols or line styles. Is anybody aware of an approach that
works well? I'm aware of issues with colour blindness and RGB versus
CMYK. Ideally I'd have something that I could just use that would deal
with all these issues. TIA.
I'd recommend looking at the Web Content Accessibility Guidelines
published by the W3C; there are a number of tools out there that are
designed to help you pick colours for a web page, and the same sorts
of rules will apply here, I think.
Also, thank you for even *thinking* about this. A lot of people don't. :)
+1
We spend a lot of time teaching this topic (non-Python courses). It
receives a lot of often highly-polarised comments/discussion. Many folk
have their 'eyes opened' to an issue which has not affected them
personally. Some even have to be informed that it is a legal obligation
in their jurisdiction. However, it also receives the highest number of
'why do I have to learn this stuff' complaints...
I learned (way back) that the incidence of "color blindness" is far
higher than I had imagined. Secondly, that it affects males more than
females. Thirdly, that calling it "blindness" is a bit of a misnomer,
because whilst people often can't see red 'correctly' (most common
symptom), they do see something (it varies). Which is why they are
permitted to drive vehicles (traffic lights: red, amber/yellow, green -
and arrows; plus stop/brake lights), but why many smart-phone apps/web
pages which encode information-relevance (red is 'wrong' and green/blue
is acceptable) can become almost unusable (without other cues).
Those key-words: "accessibility guidelines" will yield a swag of useful
tools - ignore the ones which are basically 'help choose the color of my
web page/color palette, because they are often aiming (only) for
'pretty'. The best tools enumerate the efficacy of fg/bg
color-combinations, allowing one to experiment; and will enumerate
grey-scale variation/comparisons.
Hmmm, note to self (you've inspired me to specifically review/critique
the printing-from-screen action): what happens when we take a
color-checked screen display and print same but end-up viewing it as
monochrome/grey-scale output? Probably not a main-stream demand, but
worth tossing at the WCAG experts...
--
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Regards =dn
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