Re: [png-mng-implement] What triggers these two libpng warnings?

[Glenn Randers-P. <gl...@gm...>]

Have you tried libpng-1.6.12 yet?  Even if you don't disable the sRGB
profile checking,
there should be fewer of the "has been edited" warnings now (I could be
wrong about
that, but I think most V2 profiles -- ones without an MD5 tag) trigger the
warning.

Otherwise I'll work harder on providing an option to eliminate the iCCP
warnings
entirely.

It is the "onerous terms" that you mentioned that got us into this mess in
the
first place.  libpng 1.6.0 through 1.6.11 don't allow writing modified
versions of
the color.org profiles, but it seems that other profiles got caught in the
crossfire.

Glenn


On Fri, Jun 13, 2014 at 5:05 PM, Elle Stone <ell...@ni...>
wrote:

> On 06/10/2014 12:22 PM, Elle Stone wrote:
> > On 06/09/2014 09:25 PM, Glenn Randers-Pehrson wrote:
>
> >> In the long run I'd like to eliminate (optionally) the entire iCCP
> >> profile-checking
> >> stuff as you suggested a little while ago, but didn't get to it in
> >> libpng-1.6.11/12.
>
> I located the reason why libpng was printing so many warnings to the
> terminal when I start Krita. Krita paintoppresets (*.kpp) have embedded
> sRGB profiles made by LCMS, as do essentially *all* sRGB images created
> with free software, except the ones with ArgyllCMS's sRGB.icm profile,
> which libpng also flags.
>
> I used exiftool to remove the embedded profiles in the Krita
> paintoppresets. Unfortunately libpng is still -checking- the
> paintoppresets, which takes quite a while to finish and sends one core
> to 100% while it's happening.
>
> Libpng emits the "Not recognizing known sRGB profile that has been
> edited" warning for sRGB profiles made/distributed by ArgyllCMS, Canon,
> Bibble, MicroSoft, Adobe, and LCMS.
>
> The -only- sRGB profiles I could find that libpng -didn't- emit a
> warning about were the two color.org sRGB profiles:
>
> sRGB_IEC61966-2-1_black_scaled.icc
> sRGB_IEC61966-2-1_no_black_scaling.icc
>
> The thing is:
>
> * Neither of the color.org profiles can be distributed by free software.
>
> * The user has to click-agree to onerous terms to download these profiles.
>
> * One of them is intended for use as a substitute for a monitor profile
> and is defective because the black point tag doesn't agree with the TRC.
> This profile has a higher than 0 black point (as determined by the TRC,
> the tag is ignored) and therefore is not a valid sRGB profile for
> embedding in actual sRGB images.
>
> It would be truly wonderful if the warnings could be eliminated.
>
>
> Elle
>
>
>
>
>
>
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