[NTG-context] overprinting black
Hi, esp. Hans, while finalizing the PDF for our latest book, I recognized a color problem: The general black color is rendered not 100% black in CMYK mode, but in all channels (converted RGB, I guess). With \definecolor[cmykblack][k=1] \setupcolors[textcolor=cmykblack] this is ok, but the color mode is knockout instead of overprint (as it would be usual for CMYK black). That means, black text on a photo is white in the other plates. If I define \definecolor[cmykblack][k=1,a=multiply,t=1] \setupcolors[textcolor=cmykblack] it’s ok in some places, but it messes up many unrelated places, e.g. most images then also use this transparency mode. \setupcolors[intent=overprint] has no effect, as far as could find (while we have a warning in the wiki, that you should use this only for grayscale works). What can I do? Hraban ___ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / https://mailman.ntg.nl/mailman3/lists/ntg-context.ntg.nl webpage : https://www.pragma-ade.nl / https://context.aanhet.net (mirror) archive : https://github.com/contextgarden/context wiki : https://wiki.contextgarden.net ___
Re: [NTG-context] overprinting black
Am 09.11.22 um 17:22 schrieb Duncan Hothersall: Have you tried overprint=yes? I have that in old files which used to work under mkii. I must admit I haven't had the need to use overprinting since then, but I do recall that come colour handling wasn't ported across to mkiv or later. Thank you for the hint, but it doesn’t work, neither in \setupcolors nor in \definecolor. Hraban ___ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / https://www.ntg.nl/mailman/listinfo/ntg-context webpage : https://www.pragma-ade.nl / http://context.aanhet.net archive : https://bitbucket.org/phg/context-mirror/commits/ wiki : https://contextgarden.net ___
Re: [NTG-context] overprinting black
Have you tried overprint=yes? I have that in old files which used to work
under mkii. I must admit I haven't had the need to use overprinting since
then, but I do recall that come colour handling wasn't ported across to
mkiv or later.
Duncan
On Wed, 9 Nov 2022 at 16:12, Henning Hraban Ramm via ntg-context <
ntg-context@ntg.nl> wrote:
> I’m not sure if this ever worked, but at least in latest LMTX it doesn’t:
>
> """
> \setupcolors[state=start,cmyk=yes,rgb=no,intent=overprint]
>
> \starttext
>
> \framed[
>background=color,
>backgroundcolor=yellow,
> ]{\ss\bfd
>Black should always overprint.
> }
>
> \stoptext
> """
>
> The black text and frame border don’t overprint the yellow background
> but knockout. The only way to check this (that I know of) is Acrobat
> Pro’s separation simulation; the screenshot shows a snippet of the
> yellow separation.
>
> Actually, setting “overprint” for all colors doesn’t make sense, it
> should be a setting for single color (but default for black):
>
> % desired interface:
> \definecolor[overBlack][k=1,intent=overprint]
>
> Hraban
>
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> the Wiki!
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[NTG-context] overprinting black
I’m not sure if this ever worked, but at least in latest LMTX it doesn’t:
"""
\setupcolors[state=start,cmyk=yes,rgb=no,intent=overprint]
\starttext
\framed[
background=color,
backgroundcolor=yellow,
]{\ss\bfd
Black should always overprint.
}
\stoptext
"""
The black text and frame border don’t overprint the yellow background
but knockout. The only way to check this (that I know of) is Acrobat
Pro’s separation simulation; the screenshot shows a snippet of the
yellow separation.
Actually, setting “overprint” for all colors doesn’t make sense, it
should be a setting for single color (but default for black):
% desired interface:
\definecolor[overBlack][k=1,intent=overprint]
Hraban
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