[pdftex] Howto activate overprint (/knockout)

[Siep Kroonenberg]

On Fri, Apr 30, 2004 at 02:40:15PM +0200, JEBs wrote:
>
> >J> I'm developing a PDF document which shall be printed by a professional
> >J> printing company.
> >
> >J> The whole document has a light-yellow background so that I need to
> >J> activate (most times, but not always) the "black overprint" option as
> >J> well known/available in PS or PDF.
> >
> >I am aware and have actually made the same thing work with the perl
> >module pdf::api2
> >There it is possible to set objects to overprint (I used it for color
> >seperation).
> >Search on CPAN and you'll find it. Be aware that though the library is
> >very powerful the documentation is rather poor since it is a "real
> >time project" which is used and developed on the demands of a real
> >project and therefore documentation is last.
> >
> >
> Yes, I'm aware that it will work and I know that it could be done with
> the PDF internal "/op", "/OP" and "/OPM" parameters.
> But my problem is how to integrate them in pdflatex.
> I figured a lot with \pdfobj, \pdfrefobj and \pdfliteral but couldn't
> get a working solution.
> I get the object in but don't get them used/referenced nor working.
> I'm sure that I'm doing something stupidly wrong but don't know what :/.
> In addition I couldn't find any real useful docs/samples about the use
> of the extended \pdf... commands.
>
> Any more suggestions ?
>
> Cya
>    JEBs

Maybe a variant black with yellow in it would solve your problem.

--
Siep Kroonenberg
siepo at cybercomm.nl