Overprinting black in Publisher - what counts as black?

[Bobbob]

Hi,

what counts as "black" for automatic overprinting of black in Publisher? Is it just 0%C 0%M 0%Y 100%K, or will any colour with 100%K automatically overprint? 

And is there any way to check that overprint is set correctly in the output PDF without Acrobat Pro?

thanks

Currently using 2.2.0 on Win 10

[loukash]

K always overprints unless you uncheck the Overprint Black global option in the PDF export Advanced panel.

Some printers should also have a global K Overprint option in their respective print dialog. My old Oki c5450n does. (Printing directly from Affinity apps on Mac always was a p.i.t.a. though. I go via PDF whenever possible.)

[loukash]

2 hours ago, Bobbob said:

is there any way to check that overprint is set correctly in the output PDF without Acrobat Pro?

• Packzview – if they consider that you're worthy of their generous free license
• Ghostscript – on Mac you can install it as a *.pkg and then run a shell script to generate TIFF separations, works also via Automator or Shortcuts as a Service/Quick Action plugin (didn't I post one here on the forums some time ago?)
• (PDF Studio to some degree – the demo doesn't seem to be time limited and seems to work OK as a PDF/X preflight checker, but the output preview can't even handle spot colors, let alone display overprint properly…)

Also note that black overprint doesn't work with K gradients.
To overprint a gradient, you may need to set its blend mode to Darken or Multiply. PDF versions that don't support transparency will then rasterize everything underneath. PDF/X-4 should handle the basic blend modes fine though, without rasterizing.

@Serif, we really need an object based overprint attribute!

[loukash]

8 minutes ago, loukash said:

(didn't I post one here on the forums some time ago?)

Obviously not yet.

But @iPeter has posted this AppleScript collection: 

 

[loukash]

1 hour ago, loukash said:

Also note that black overprint doesn't work with K gradients.
To overprint a gradient, you may need to set its blend mode to Darken or Multiply. PDF versions that don't support transparency will then rasterize everything underneath. PDF/X-4 should handle the basic blend modes fine though, without rasterizing.

Alright, found an old thread where we've discussed similar issue – and related bugs – before:

To work around the bug – still present as of v2.2.0 FFS! – you must follow this insane voodoo ritual as demonstrated in my screencast from 2021 if you want a K gradient overprint: 

[loukash]

2 hours ago, anto said:

Partly yes, using Photo Persona and channels.

Well, this is exactly the point that you can't check overprint this way…

[loukash]

3 minutes ago, anto said:

check that it is a real black color

Fair enough, that's at least something, even though not much…  
It will still give you a false impression though, exactly because it completely ignores overprint.

As far as I can tell, the best free and platform independent solution is Ghostscript, then you can also preview the resulting TIFF separations as Affinity layers by setting them to Multiply blend mode. That can be surely scripted on Windows by some means as well, akin to the aforementioned @iPeter's AppleScript solution. 

[Bobbob]

2 hours ago, loukash said:

As far as I can tell, the best free and platform independent solution is Ghostscript, then you can also preview the resulting TIFF separations as Affinity layers by setting them to Multiply blend mode. That can be surely scripted on Windows by some means as well, akin to the aforementioned @iPeter's AppleScript solution. 

Perfect!* I hadn't thought of using Ghostscript (only ever used gs to convert from PS to PDF, didn't realise it worked the other way around too). Just checked and gs -sDEVICE=tiff32nc does the trick, and confirms it's just 100%K that overprints automatically. You've just saved me an Acrobat subscription 😄

 

*well, more perfect would be having basic vital functionality like this implemented within Affinity but I think Serif have made it pretty clear they have no intention of catering for even the occasional prepress user.

[Bobbob]

I didn't read it anywhere. I meant they've made it clear through their actions (or lack of them). Looking through the forums people have been asking for basic print-related features like this for years and years with absolute silence and from Serif.

[loukash]

4 minutes ago, Bobbob said:

gs -sDEVICE=tiff32nc does the trick

My Automator command goes: 

gs -q -sDEVICE=tiffsep -r300 -dTextAlphaBits=4 -o "$2"/output%d.tif "$1"

… where the $1 variable is the file passed from the macro input. I don't remember what exactly each option means but it should be all explained in the gs documentation somewhere.

[Bobbob]

53 minutes ago, anto said:

This is probably because the "pre-basics" are not still working well. They still have time.

How much time do they want? I've been using Publisher for three or four years now. I've stupidly paid for the underwhelming v2 update. I won't be sticking around much longer if they can't sort out "pre-basics". I love designing in Publisher, but sending a job to print you're basically flying blind.

[Bobbob]

20 minutes ago, loukash said:

My Automator command goes: 

gs -q -sDEVICE=tiffsep -r300 -dTextAlphaBits=4 -o "$2"/output%d.tif "$1"

tiffsep and tiff32nc seem to produce the same 32bit CMYK tiff file, but tiffsep also produces a separate greyscale file for each separation.

[lacerto]

Obsolete.

[lacerto]

Obsolete.

[Bobbob]

35 minutes ago, lacerto said:

But considering the continuing poor availability of free (or even low-cost) professional prepress tools being able to show e.g. spot colors, pick color values, show total area coverage and overprints, I decided to update the tool, and it now supports also version 2 Affinity apps on both Windows and macOS.

 

Thanks! Will have a look at this. There certainly seems to be a gap in the market for such a tool. None of the many available PDF viewers seems to be geared towards prepress. Free would be ideal, but cheaper than £20/month would be a start.

 

[Dan C]

@loukash

We're looking into this currently and will get it logged with the devs.

Lee