Re: Bug with overprinting in Mark II/IV?

[Peter Rolf <indiego@gmx.net>]

Oliver Heins schrieb:
> Hello,
>
> with color black overprinting is not working.  You can easily spot this
> when you use the »Ausgabevorschau« (sorry, my acrobat is in german
> locale, must be something with »preview« in english; located in the
> »tools« menu) in acrobat and remove magenta and black from the preview.
> Whilst under the region with the magenta colored text the picture gets
> shown, in the region with the black colored text the text is cut out of
> the picture, leaving white.
>
>   
I think the visible 'knockedout' text on the picture is just another 
acrobat bug. I manually checked the text and the OVP attributes are 
correctly set. If you use the coloring mechanism (Ausgabenvorschau -> 
Farbwarnungen -> [x] Überdruck anzeigen), you will see that everything 
looks ok.

> I think this is a bug, as overprinting makes most sense with black.  It
> happens both in Mark II and IV -- you have to manually copy the
> hacker.jpg to your working directory (under linux e.g. with cp
> $(kpsewhich hacker.jpg) /path/to/your/working/directory) and change the
> path to make the minimal example work under mark iv.
>
>   
I noticed this too (no picture with mkiv). BOF = Bug Or Feature :)

> Best regards,
>  olli
>
> \setupcolors[state=start,cmyk=yes,rgb=no]
>
> \definelayer	[mybg]
> 		[x=0mm, y=0mm,
> 		width=\paperwidth, height=\paperheight,
>                 repeat=yes]
> \setlayer	[mybg]
> 		[hoffset=5cm, voffset=7cm]
> 		{\externalfigure[sample/hacker.jpg][max]} % mark ii
> %		{\externalfigure[hacker.jpg][max]} % mark iv
> \setupbackgrounds[page][background=mybg]
>
> \starttext
>
> {\bf With foregroundcolor = magenta.}
> \color[magenta]
>
> \startoverprint
> \input tufte
> \stopoverprint
>
> \color[black]
> {\bf With foregroundcolor = black. \color[magenta](Some magenta
>   without overprint)}
> \color[black]
>
> \startoverprint
> \input tufte
> \stopoverprint
>
> \stoptext
>
>   

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