GNOME Bugzilla – Bug 26805
PostScript colour output looks pale
Last modified: 2007-05-11 11:56:07 UTC
Package: gimp Version: 1.2 prerelease Name........: Pascal Email.......: a.haakmat@chello.nl Platform....: GIMP Version: 1.2 prerelease GTK Version.: 1.0.6 WM/Version..: Enlightenment 0.16.3 -- Other system notes: -- -- Problem description: When printing an image (either indexed colour or RGB) to a PostScript file, the resulting PostScript image looks very pale. Adjusting the gamma and density helps somewhat, but the tiff2ps tool generates much better output without any color adjustments. -- -- How to repeat: Create a colorful TIFF image. Print it to a PostScript file. View the PostScript file with gv. To verify that the image is actually too pale, do this: Create a colorful TIFF image. Use tiff2ps to convert it to an EPS. View the EPS using gv. -- -- Other comments: Good luck. -- ------- Additional Comments From a.haakmat@chello.nl 2000-10-04 21:36:43 ---- Subject: regarding versioning From: Pascal Haakmat <a.haakmat@chello.nl> To: 26805@bugs.gnome.org Message-Id: <20001005033643.A32664@awacs.dhs.org> Date: Thu, 5 Oct 2000 03:36:43 +0200 hi, the bug i submitted is using version 1.1.26 of the gimp. ------- Bug moved to this database by debbugs-export@bugzilla.gnome.org 2001-01-28 11:01 ------- This bug was previously known as bug 26805 at http://bugs.gnome.org/ http://bugs.gnome.org/show_bug.cgi?id=26805 Originally filed under the gimp product and general component. The original reporter (a.haakmat@chello.nl) of this bug does not have an account here. Reassigning to the exporter, debbugs-export@bugzilla.gnome.org. Reassigning to the default owner of the component, egger@suse.de.
Re-assigning all Gimp bugs to default component owner (Gimp bugs list)
Looks like a wish for some color settings in the PS save plugin. Assigning to current CVS because it's a wishlist item.
Bumping a bunch of enhancement requests which will not be done by the feature freeze to Future. Dave.
I wil address this while working on "part 7" of BUG 138583 However, when I get there, I will surelly open another bug to track color corrections issues, so no need to mark this as "depending on 138583". If the orginal reporter did not die of old by now, please watch BUG 138583 , and make sugestions there.
The sRGB web site has public domain PostScript code for setting up the right color space. Since the code is short and that site is about to die (the top-level page says it is no longer available) I will include the code here. Google might keep a cache around for a bit longer; query for "srgb" and "postscript" to see it. It survives for the moment at: http://www.srgb.com/srgbpostscript.html %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% [ /CIEBasedABC << % sRGB gamma transform /DecodeLMN [ {dup 0.03928 le {12.92321 div}{0.055 add 1.055 div 2.4 exp}ifelse} bind dup dup ] % sRGB to XYZ (D65) matrix (ITU-R BT.709-2 Primaries) /MatrixLMN [ 0.412457 0.212673 0.019334 0.357576 0.715152 0.119192 0.180437 0.072175 0.950301 ] /WhitePoint [ 0.9505 1 1.0890 ] % D65 /BlackPoint[0 0 0] >> ] setcolorspace %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% << % sRGB output CRD, D65 white point /ColorRenderingType 1 /RangePQR [ -0.5 2 -0.5 2 -0.5 2 ] % Bradford Cone Space /MatrixPQR [0.8951 -0.7502 0.0389 0.2664 1.7135 -0.0685 -0.1614 0.0367 1.0296] % VonKries-like transform in Bradford Cone Space /TransformPQR [{exch pop exch 3 get mul exch pop exch 3 get div} bind {exch pop exch 4 get mul exch pop exch 4 get div} bind {exch pop exch 5 get mul exch pop exch 5 get div} bind] /MatrixLMN [3.240449 -0.969265 0.055643 -1.537136 1.876011 -0.204026 -0.498531 0.041556 1.057229] % Inverse sRGB gamma transform /EncodeABC [{dup 0.00304 le {12.92321 mul} {1 2.4 div exp 1.055 mul 0.055 sub}ifelse} bind dup dup] /WhitePoint[0.9505 1 1.0890] % D65 /BlackPoint [0 0 0] >> setcolorrendering %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
It should be easy to add above postscript code to the plug-in. Any volunteers?
Well, this is tricky stuff. According to the Postscript Level 2 Reference Manual, "setcolorrendering sets a graphics state parameter whose effect is device dependent. It should not be used in a page description that is intended to be device independent." It is also a Level 2 postscript command. I think this should not be fooled with by people who don't really know what they are doing (such as me). Bumping target on this accordingly.
I can't reproduce this problem any longer. Closing as OBSOLETE.