Re: [matplotlib-devel] Better defaults all around?

[Todd <tod...@gm...>]

On Nov 26, 2014 10:04 PM, "Nathaniel Smith" <nj...@po...> wrote:
>
> On Wed, Nov 26, 2014 at 9:30 AM, Todd <tod...@gm...> wrote:
> > On Sat, Nov 22, 2014 at 12:22 AM, Nathaniel Smith <nj...@po...> wrote:
> >>
> >> - Default line colors: The rgbcmyk color cycle for line plots doesn't
> >> appear to be based on any real theory about visualization -- it's just
> >> the corners of the RGB color cube, which is a highly perceptually
> >> non-uniform space. The resulting lines aren't terribly high contrast
> >> against the default white background, and the different colors have
> >> varying luminance that makes some lines "pop out" more than others.
> >>
> >> Seaborn's default is to use a nice isoluminant variant on matplotlib's
> >> default:
> >>
> >>
http://web.stanford.edu/~mwaskom/software/seaborn/tutorial/aesthetics.html
> >> ggplot2 uses isoluminant colors with maximally-separated hues, which
> >> also works well. E.g.:
> >>
> >>
http://www.cookbook-r.com/Graphs/Colors_%28ggplot2%29/ggplot2_scale_hue_colors_l45.png
> >
> > About this, I am not expert so forgive me if this is nonsensical.
However,
> > it would seem to me that these requirements are basically the same as
the
> > requirements for the new default colormap that prompted this whole
> > discussion.  So, rather than create two inconsistent set of colors that
> > accomplish similar goals, might it be better to instead use the default
> > colormap for the line colors?  You could pick "N" equally-spaced colors
from
> > the colormap and use those as the line colors.
>
> The main differences in requirements are:
> - for the color cycle, you want isoluminant colors, to avoid the issue
> where one line is glaring bright red and one is barely-visible-grey.
> For general-purpose 2d colormaps, though, you almost always want the
> luminance to vary to help distinguish colors from each other.

If you used isoluminance colors for the lines, wouldn't that mean a plot
printed in grayscale would have all lines be the same shade of gray?