Re: [hackers] [farbfeld] Mandate "ProPhoto RGB" color space for farbfeld and handle ICC profiles || FRIGN

From: Dimitris Papastamos <>
Date: Sun, 17 Jan 2016 10:10:19 +0000

On Sun, Jan 17, 2016 at 02:12:53AM +0100, wrote:
> commit 3bc6c69ae8ff25377848b76a25494aa4a0055544
> Author: FRIGN <>
> AuthorDate: Sun Jan 17 01:39:36 2016 +0100
> Commit: FRIGN <>
> CommitDate: Sun Jan 17 02:11:54 2016 +0100
> Mandate "ProPhoto RGB" color space for farbfeld and handle ICC profiles
> I've literally been thinking about this for quite a while now. The
> initial motivation behind defaulting to sRGB was the idea that most data
> on the web was in sRGB anyway.
> However, my assumption was weakened in the sense that the development
> is clearly moving towards images with supplied ICC profiles and software
> slowly catching up to handle this. My tests have shown that more and
> more people even do that on the web, even though it's been a "tradition"
> that Photoshop users "Save for Web" and convert the gamut lossy into
> sRGB to bring a consistent color-"experience" even to those clients not
> supporting ICC profiles and which always assume sRGB.
> What made this decision so difficult is that converting to "ProPhoto
> RGB" requires some advanced knowledge on this topic, however, I came to
> the conclusion to implement it given the *2ff- and ff2*-tools handle it
> silently and well in the background, and given the little cms library is
> actually quite okay to use.
> When converting from ff to png, a proper "Pro Photo RGB" ICC V4-profile is
> automatically included in the exported png by ff2png. V4 is not as
> widespread as V2, but in the worst case (no V4 support somewhere) the
> colors will just be a little off.
> As an added bonus, any input files for png2ff which include ICC profiles
> are also correctly handled and the color space conversions are executed
> as expected.
> Accordingly, the FORMAT-specification has been changed. While at it,
> I added the note on alpha-multiplication. Now the format is very exact
> and shouldn't leave any ambiguities.
> jpeg supports ICC profiles as well, but I hadn't had the chance to look
> into it (not as trivial as PNG probably, help appreciated :)), so I'm
> always assuming sRGB here.
> Rationale
> ---------
> It is not obvious why one would go through the lenghts of supporting
> this big-gamut colorspace and not just stick with sRGB. In 99% of the
> cases, there's no reason to do that, but with even more extreme
> developments in the OLED-sector and other advances display hardware is
> slowly getting more powerful than sRGB, asking for color information
> which is suitable for the task and actually uses the full potential.
> The decision in this regard was not difficult in farbfeld because we
> always use 16-Bit anyway and won't have to fear posterization in a big-
> gamut color-space.

Commit message reads like a diary.
Received on Sun Jan 17 2016 - 11:10:19 CET

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