Got a question about Prinergy Connect 5.2 and "enable gray overprint"

[cementary]

We've run into some troubles with our standard refine template.

In our refine template the setting "enable overprint gray" under the color convert page is checked. We've run through this template tons of files and there weren't any problems ever.

But this time we've got a pdf file for print with some kind a "strange" structure. There are 2 images in file: first is gray-based with overprint on (opm 1) and the second cmyk-based with overprint on (opm 1) laying under the first one. As i understand from pdf reference 1.6 the printing result of such images combination is gonna be knockout on the first image.

After refine the first image became 1 spot monotone-based (separation: black) with overprint on (opm 1). The problem is that this image is white rectangle used as a background in a table. So, at the output there was no background at all (see the file attached). We didn't see that, client didn't see that in files for approval and this file was printed as the "after refine" in the attached file.

This is the first time in five years working we've got 10.000 rejected books because of one damn checkbox.

So my question is what option do you use in your refine templates: "enable gray overprint" on or off? Did you ever have any troubles with this checkbox?
I need to make a decision if turning this option on or off by the default.

ps sorry for poor english

 

[Stephen Marsh]

Is there any chance that you could provide a simplified version or a crop of the original so that I can do some tests with my Prinergy setup (I understand that you may not wish to release the true originals)?


Stephen Marsh

 

[cementary]

The files

The files

Ok, here you are, the files.
I just removed logo and text.
+ our color convert settings

edit: files were reloaded due to some unnecessary files in it

 

[JoeatData]

My company is currently at Prinergy 5.1.2.3 and we've been using Prinergy since 4.0.
We have refined numerous jobs. We have never had this issue you are showing. The Enable Gray to Overprint has always been check off, like yours.

Your setting are exactly like mine. I am not sure if it's because of the different versions or not.

What I do see within your PDF it shows as a spot black. I am not sure why turning off the Enable Gray Overprint would affect it? I've played with the settings a few times. I haven't been able to produce your issue.

Sorry, I don't have an answer for you. I just wanted to say that I've refined 1000's of PDF's and haven't experienced what you have.

I am interested in seeing what other Prinergy users have to add. It would be interesting to know if there is a certain situation I may have to look out for.

 

[cementary]

2 JoeatData

it shows spot black, yes, but after the refine. before – there is gray. I'll try to explain with images

edit: add 1 image

 

[Stephen Marsh]

I could not re-create this issue using Prinergy Powerpack 5.3.0.0 using the standard/default Refine/Normalise process template.

Screenshot attached of settings and the refined PDF viewed in Acrobat Reader (overprint preview set to always).

When I open the original PDF in Illustrator, the white image background is indicated as set to overprint and output preview in Illustrator correctly shows the same result as your refined error.

What program is making this PDF (I looked at the metadata but did not recognise it).


Stephen Marsh

 

[cementary]

Pdf-producer is teTeX, based on donald knut's TeX but for unix. teTeX isn't supported since 2006.
dvips is "DVI-to-PostScript translator"

 

[cementary]

Stephen Marsh

Could you please repeat your test on files but this time with checkbox "colorconvert" on
'cause 1srRef-Normz didn't use this section by default

 

[Stephen Marsh]

Sorry about that, I messed up!

I tried two more tests, I refined the 1st refine using a 2nd refine with colourmatch and I also refined directly from input to 2nd refine. Both results are the same - I could not recreate your issue.

When I opened the refined PDF in Illustrator, the white image is no longer set to overprint, it is now knocking out.

http://www.enfocus.com/manuals/ReferenceGuide/PP/10/enUS/en-us/concept/c_aa1152933.html

As the refine process template was set to convert overprinting CMYK whites to knockout.

So Prinergy Powerpack 5.3 is correcting the file and is not showing the same issue as you experienced. I have attached the 2nd refine PDF and a screen capture of the 2nd refine settings.


Stephen Marsh

 

[cementary]

As the refine process template was set to convert overprinting CMYK whites to knockout.

Stephen Marsh

Sorry, but nope. This is because of setting named "Set colors to knockout".
Could you try once again with that box unchecked?

 

[Stephen Marsh]

Sorry, but nope. This is because of setting named "Set colors to knockout".
Could you try once again with that box unchecked?

So much for my assumptions (just as well I am not a Prinergy operator, I currently just know enough to be dangerous)!

Bingo, I can recreate your issue by unchecking the “Set Colours to Knockout” box… Which leads me to ask - why? Why would you uncheck this option’s box in a “normal” day to day workflow? For packaging, I can see why this may be off, however for general print and books etc, it is probably safer on than off. From the Prinergy help guide:

“Select this check box to override the overprint setting in the input file and knock out the colours”.

For packaging, I can understand how some files are setup for white or colours to overprint and this is a required feature. For non packaging work, the default would be to ignore white overprints and to knockout colours (yes, there may be exceptions).

Why does this PDF have a white box (image) that clearly should knockout, set to overprint?

P.S. The built in Acrobat preflight routines do not flag this overprinting white image. PitStop Pro 12 preflight does pick this up when using an appropriate profile such as a Ghent profile.

EDIT: Converting the image in Acrobat Pro to say CMYK removes the overprint info.


Stephen Marsh

 

[cementary]

Ouch...
That's time for me to say: I guess i've messed up.
Need to make some tests with this option, but i think that's the "problem-maker".
And smth tells me that some time ago this checkbox was on, 'case our "prepress guide for customers" aware them, that their overprint settings will be overrided by our "overprint on colors: off"

Anyway, i really appreciate your help. Thanks a lot!

 

[Stephen Marsh]

Ouch...
That's time for me to say: I guess i've messed up.
Need to make some tests with this option, but i think that's the "problem-maker".
And smth tells me that some time ago this checkbox was on, 'case our "prepress guide for customers" aware them, that their overprint settings will be overrided by our "overprint on colors: off"

Anyway, i really appreciate your help. Thanks a lot!

We have both learned something!

This is a good example of a “non standard” print publishing program creating a PDF that has some “non standard content”. This table should clearly be vector based and it should not have a white image that is intended to knockout set to overprint!

This is a good case in point that it pays to have a good preflight system in place, perhaps using multiple preflight setups from different sources. Even with overprint preview turned on in Acrobat Pro or Reader, this white box displayed as a knockout. When I opened the PDF into Illustrator and turned on overprint preview, this white box displayed as an overprint.

Even though PitStop Pro 12 picks up this white greyscale mode image set to overprint, not everybody is using PitStop Pro. I tried making a custom preflight in Acrobat Pro, however it did not detect this image when it should. Perhaps it was just the way I setup the custom check that was wrong…


Stephen Marsh