Re: [Gimp-developer] High bit depth assets to GIMP 2.10

[Elle Stone <ellestone ninedegreesbelow com>]

On 10/22/2016 08:50 PM, Americo Gobbo wrote:
> Hi All,
> Is possible discuss again the possibility to have assets in 16 and 32
> bit, mainly the palettes and patterns.
> The initial discussion was proposed by Alexandre Prokoudine, in 2014 >
> https://mail.gnome.org/archives/gimp-developer-list/2014-February/msg00050.html

That's an interesting discussion. Here's a link to the Nabble archive 
(makes it easier to read the entire thread):

http://gimp.1065349.n5.nabble.com/assets-in-the-high-bith-depth-age-td41929.html

I would very much like to see palettes and such stored using 32f 
floating point LCH rather than 8-bit RGB, for two reasons:

1. Eight-bit precision is insufficient precision for storing linear 
gamma color information - darker colors are severely posterized upon 
being saved to disk, to the point where the human eye can see that the 
color has changed.

2. LCH is independent of the RGB color space, which means "color 
managing" the LCH assets is a matter of converting from the stored LCH 
values to whatever RGB working space the user happens to be using. Which 
for GIMP 2.10 really should be sRGB, but as indicated by the Roadmap for 
future versions of babl/GEGL/GIMP this will change.

Has Krita moved on past the 8-bit assets? If so what is Krita using to 
store palettes and such?

16-bit integer would be enough to store "more precision than the eye can 
see", but wouldn't allow to store colors that are outside the display 
range, whereas high bit depth GIMP's (rather babl's, with supporting 
unclamped operations in GEGL and GIMP) RGB/XYZ/LAB/LCH color conversions 
do allow to calculate and store out-of-display-range colors.

Elle