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From: "Hartmut Henkel" <hartmut_henkel@gmx.de>
To: mailing list for ConTeXt users <ntg-context@ntg.nl>, ntg-context@ntg.nl
Subject: Re: compresslevel and png graphics (mkiv)
Date: Fri, 27 May 2011 15:09:14 +0200	[thread overview]
Message-ID: <20110527130914.171040@gmx.net> (raw)
In-Reply-To: <4DDF91BF.8030806@gmx.net>

> > @luigi: an ICC profile definitely breaks the <png copy> rules
> > 
> > The only chunks left are
> > 
> > IHDR    PNG image header: 5900x4094, 8bits/sample, truecolor,
> noninterlaced
> > IDAT    PNG image data
> > ..
> > IDAT    PNG image data
> > IEND    end-of-image marker
> > 
> > Mh, where is the show stopper? The compression method?
> >
> Looks like some of ConTeXt PDF/X-related settings is causing this. If I
> reduce the code to the pure picture, the '(PNG copy)' is triggered.
> Probably the active color management (default color space) is breaking
> the copy process here.

must be some \pdfimageapplygamma > 0, only this and the \pdfimagehicolor
primitive can influence this low level stuff.

Btw, just \pdfimageapplygamma > 0 (without setting \pdfgamma and \pdfimagegamma) already changes the PNG image, since the luatex (and pdftex) internal defaults are not gamma-neutral. No idea if (and then
to which value) this should be fixed.

Regards, Hartmut
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  reply	other threads:[~2011-05-27 13:09 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-25 12:43 Peter Rolf
2011-05-25 14:39 ` Hans Hagen
2011-05-25 14:48   ` Taco Hoekwater
2011-05-25 16:05     ` Peter Rolf
2011-05-25 19:54   ` Hartmut Henkel
2011-05-26 10:52     ` Peter Rolf
2011-05-26 11:22       ` luigi scarso
2011-05-26 16:17       ` Peter Rolf
2011-05-27 11:57         ` Peter Rolf
2011-05-27 13:09           ` Hartmut Henkel [this message]
2011-05-27 15:11             ` Peter Rolf
2011-05-27 15:19               ` luigi scarso
2011-05-27 15:34                 ` Peter Rolf
2011-05-25 14:40 ` Hans Hagen
2011-05-26 17:32   ` mathew
2011-05-26 17:43     ` mathew
2011-05-27  6:17       ` Henning Hraban Ramm
2011-05-27  7:43         ` Hans Hagen
2011-05-26 17:55     ` mathew
2011-05-26 17:58   ` Martin Schröder
2011-05-26 22:52   ` George N. White III

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