Hans Hagen schrieb: > Peter Rolf wrote: > >> Well, it seems that my formulation was too fuzzy (its out of question >> that overprinting is implemented). Anyhow, its time to test it again. >> This code fails here and at ConTeXt live (online). >> >> >> \setupcolors[state=start] >> >> \starttext >> >> No overprinting. >> >> \startoverprint >> Overprinting is active. >> \stopoverprint >> >> \stoptext > > run ok here, but the question is .. what exactly do you expect to see >
to be exact: some orange text :) Acrobat8 menu 'Advanced'-->'Print Production'-->'Output Preview...' [Output Preview Window] - select 'Color Warnings' entry in the 'Preview' listbox - check the now visible 'Show Overprinting' checkbox Now all overprinting stuff is shown in the selected color (orange). Well, at least should... After comparing the pdftex and the luatex pdf files, I found a difference in the used overprinting modes. pdftex uses the 'Standard Overprinting Mode' (OPM 0) here and luatex the 'Illustrator Overprinting Mode' (OPM 1). This is probably the reason why the overprinting is not shown in orange in the prior described output preview. So its no ConTeXt related problem (overprinting attribute is set), but more a bug or at least missing feature in Acrobat8. I have to read more about the differences between the two modes. What I have found out so far (no guarantee): - 'OPM 0' overprints only on gray and spot colors (which makes it nearly useless for my needs) - 'OPM 1' can overprint on CMYK, but only if the RIP is capable of Postscript Level 3. If any color channel of the overprinting color is at 0%, the overprinting is done channelwise (which means the corresponding channel of the underlying color is visible in case of the 0% channel; so knockout should be used here instead of overprinting) - Also overprinting in general only works if no ICC-profile is attached to the object Sigh, prepress problems. Sorry for the noise! Peter ___________________________________________________________________________________ If your question is of interest to others as well, please add an entry to the Wiki! maillist : ntg-context@ntg.nl / http://www.ntg.nl/mailman/listinfo/ntg-context webpage : http://www.pragma-ade.nl / http://tex.aanhet.net archive : https://foundry.supelec.fr/projects/contextrev/ wiki : http://contextgarden.net ___________________________________________________________________________________
