Re: [Gimp-user] Does Gimp support more than 8 bits per color channel?

["Liam R. E. Quin" <liam fromoldbooks org>]

On Fri, 2017-10-20 at 17:10 -0200, Joao S. O. Bueno wrote:
> 8bits per color component is more than you eye can distinguish
> already, so if these 10 bit components cost extra, don't go for them.

Try a gradient from blue to white on a 1,000-pixel wide image and say
you don't see banding. The answer to this is not dithering, because
then if you have multiple layers composited you start to see other
artifacts - this is part of why the movie industry uses higher bit
depth, as neither sharp bands in the sky nor flickering like a 1900s
silent film was acceptable to them. And if the monitor can't display
what's being edited then there's guesswork involved.


> Contrast is another thing: you should aim for good monitor contrast
> ,where black is black.
Yes. And a wider gamut such as AdobeRGB really does help, too
especially if you're working with images for print. Monitors that do
higher bit depth often also have a wider display gamut, e.g. so you can
see saturated reds and oranges.

> So, detailing the display parts: I don't know if x11 or Wayland
> support 10bpp for display use. Anyway, GIMP uses GTK2 + Cairo for
> doing the interface, and those sure are 8bpp only.

I don't think it wise to guess :)

In fact X11 has supported higher bit depths for decades, partly because
of SGI graphic systems used in film production.

However, gtk2 does have the problems i mentioned in my earlier message,
so it might be worth waiting for the gtk3 version of gimp to be stable
before using 10 bits per channel in the display. Also, i've been told
krita is OK with it but i haven't tested that recently.

If you get an 8-bit-per-channel monitor here it's hard to get one that
does more than 6-bit on the blue channel by the way - you have to go to
a place selling monitors for graphic design (e.g. Vistek in Toronto) or
buy one unseen via this new-fangled Web thing.

Note also that a hardware colour calibration device is pretty essential
if you're going to spend the extra money for a high quality screen.

Liam