White Overprint setting?

[alan_ruta@adobeforums.com]

I'm not sure where to post this (so I've posted it here and within "InDesign"), but I need help agaisnt the big guy (a big push you around printer).

We received a file that had soej whitle illustrator type set to over print. When we ran composites to our Epson fiery RIP, Best Color Rip, B@ seps to a laser writer, film seps to our Avantra with Viper (pretty old) RIP and Kodak Approval XP4 with Harlequinn 5.1 RIP.

In every case the white type knocked out (as you would want, but not what the file read. However when the printers that prints the magazine used the file the type did overprint. Are most RIPs set to NOT overprint whilte objects. Is there a way to avoid this in the future? If we turn off presever overprint settings the black type no longer ko.s.

Any advice is welcome.

alan ruta

[Jon_Bessant@adobeforums.com]

Alan,

Different processes do handle overprint differently. However, you need
to be 100% sure the objects overprinted or knocked out to begin with -
period.

*Use products such as Quiterevealing or Enfocus Pitstop to check.*

Distiller's option to 'preserve overprint' is a global setting -
therefore if you turn ON it will honour any knockout/overprint settings
- period. This is your decision, please bear in mind that any overprints
will then obviously change to knockout - there might be objects which
have been configured as overprint as a design or faux trapping feature.

Yes, certains workflows and/or RIPs have been configured to either
honour or globally over-ride overprints. Sometimes this is good (if
their system fixes your file) - sometimes this is bad (if their system
breaks your file). The only true system which complies with correctly
presented files (including PDF/X) is for a system to honour the content.

Your remarks about running the file as a composite - this does not
always work .. as a matter of interest, it will only work printing from
Acrobat if you select 'Simulate overprint' in the print/advanced menu.
Also, ensure you have the 'overprint preview' mode switched ON under the
VIEW menu (Acrobat 5) or the ADVANCED menu (Acrobat 6).

The crux is this as stage 1 is to see if you created the problem or the
printer .... from here we can then ascertain the best way forward.

Jon

[Aandi_Inston@adobeforums.com]

The PDF/X3 standard was the first to mandate a specific behaviour. If
I remember correctly, it is that overprinted white objects are NOT
treated specially. And if they are not treated specially, they will
disappear.

The behaviour doesn't only depend on the RIP but on the tools used to
separate the file. For instance: placed into XPress; white overprint
is visible always. On-host separations from Acrobat; white always
disappears.

In-RIP separations are even more complex. Process will not always
honour overprint. Level 2 Adobe RIPs will not. Level 3 Adobe RIPs will
process overprint on process, and white is invisible. Harlequin RIPs
have a switch - you choose.

(My company's) Quite Revealing plug-in can be used to test a
particular separation workflow, and then set up to preview separations
to match the workflow.

Aandi Inston

[alan_ruta@adobeforums.com]

Thanks, Jon and Aandi.

I found and older post of Aandi's that lists 6 or 7 workflows and how half seem to allow the white overprint and half do not. There is little consistency. What would be best is to preserve black and rich black overprint settings but not white overprint.

Perhaps in a silkscreen job white overprint might be needed, but that is a rarer instance. In that case I would make the white a spot color to avoid confusion.

--alan