On Wed, Feb 7, 2018 at 6:15 AM, Máirín Duffy <duffy(a)fedoraproject.org>
wrote:
Hi Chris,
On 02/06/2018 06:09 PM, Chris Murphy wrote:
> On Tue, Feb 6, 2018 at 9:17 AM, Máirín Duffy <duffy(a)fedoraproject.org>
> wrote:
>
> 3) Green as a color for digital display is somewhat problematic as it is
>> the
>> color with the poorest coverage in the sRGB color gamut, meaning across
>> various displays it can appear very different, making it an inconsistent
>> color for branding. (see [7], figure 4 for a diagram of the gamut)
>>
>
And more sensitive to hue error in achromatic color than chromatic
> color. So there's really all kinds of ways for color matching to fail
> and just avoiding greens isn't going to improve the chance of a color
> match.
>
LOL I was actually hoping you might jump in with a more informed
background on the issue :)
I'm not saying green should be avoided entirely, but if it was the main
color of a background.... I'm just not sure it works out the best. One of
the Fedora "Four Fs" is a bright green and we've had some issues with it.
(Maybe more with printing than display tho)
It depends on the scene, there is such a thing as memory colors, like green
grass. So even if we're nut fussy about accurate rendering of green in
general, we can become fussy via object recognition, and finding green
grass being a bit too blue or too yellow and finding that objectionable.
The same problem happens with skin tones.
Maybe incorporating the "four f's" colors into one of
the backgrounds
could help make the background more colorful though. We've tried to stay
pretty blue because the few times we tried to veer off we got a lot of
negative feedback, although the latest background (jellyfish) has a
blue-purple gradient and I've honestly not seen a bad thing written about
it.
The biggest problem we're likely to face are images with smooth gradients.
Laptop panels are shit, and you'll see more complaints about
banding/posterization due to images that expose defects resulting from the
low bitdepth of most laptop panels. This is easy to deal with, just add
noise. If the scene is blue sky, pick the image with even a few wispy
clouds to break up the gradient. Or even in this case maybe avoid blue sky
images because the sky isn't really blue, it's more cyan and displays don't
do a great job of reproducing that color, and it's also a memory color. If
it tracks a bit blue or a bit yellow on some displays, people will abruptly
become aware of it.
Likewise, neutral images will be a bugaboo because the gray balance of most
consumer displays meanders throughout the tone curve. A neutral image will
just expose panel deficiency, unless the image can depend on being duo or
tri toned, which actually might be kind fun to play around with... or
totally insane.
There's a whole area of psychophysics research on what constitutes
emotionally neutral imagery. It's important to have various test images
that don't evoke an emotional response when doing human testing in image
quality evaluations because you don't want the person injecting unrelated
bias into the results.
I suspect what's going on with the latest background is two fold: it's such
an artificial blue-purple color that it in no way makes people try to
compare it to a memory color, it's so chromatic it's already divorced from
reality. This is actually a rendering sought after by Fuji Velvia film
affectionados. It would render forest, garden, and underwater scenes in
totally unnatural fairy tale chromatic color. There was not even the
pretense about accurately reproducing the actual scene. The other reason is
the jellyfish image probably is succeeding at being emotionally neutral.
And it has some low frequency noise throughout that breaks up the gradient
so any panel deficiency isn't noticeable.
Anyway I would think less about specific hues involved, and more about
whether the objects in the scene have certain specific hue expectations in
rendering. Making the rendering more dreamy or ethereal, while also
emotionally neutral, will help you get away with a lot of things you have
no control over.
--
Chris Murphy