Strange PDF Issue with Onyx - Any Ideas?

[jbingaman]

Good morning all,

I've had a couple of issues lately with pdfs that have been created for wide format output. (I would've posted this question in the WF forum, but figured it has more to do with pdf creation than wf printing)

So far, I've not been able to determine the issue, but I'm quite certain it has to do with the way the file was created.

Here's an example...

PDF is opened in Onyx by our wide format technician and it looks as though it wasn't properly flattened...layers that are on top show what's behind them (sometimes). I'm not sure how else to explain it...a photo that has a box of color overlaying it containing text shows through the box of color in what looks like a Photoshop Layer Blending mode set on 'Exclusion' or 'Difference'.
If the PDF is opened in Acrobat, you don't see this and it appears to be correct. It does not show that there are even any layers in the document, BUT the same pdf opened in Onyx looks problematic as described above.
So far we've found that if we open the file in Photoshop, Flatten it and Save as pdf, then open it in Onyx...it's fine.

Does anyone have a clue as to what may be the problem? It seems like it has to do with the flattening on the pdf when it's created, but as mentioned...no layers are visible in the layers pallet of Acrobat.

wtf?

Thanks in advance for any feedback!
-Jeremy

[leonardr]

Sounds like a case of improper use of Overprinting...

But without seeing the actual file in question - we'd only be guessing. Can you post it?

Leonard

[jbingaman]

I'll have to see if I can make it a little smaller...it's about 54MB.

When you say 'overprinting'...do mean incorrect in the way the pdf is created (something set wrong in IDD or Acrobat) or do you feel that it could be an 'overprint' setting within Onyx?

Thanks for the input Leonard!

[leonardr]

Could be either - or both.

Again, can't tell without the file...

Leonard

[ScottyDoo]

Does your file have a combo of raster and vector elements?

There are known transparency issues with PDF's when it comes to raster effects on top of vector elements. An example being that often times a designer will add drop shadow to some text in Illustrator. That's all fine and dandy, but that drop shadow is now a raster element, so when you load the file into Onyx, it renders the raster and the vector differently so you will see a box around the text that is a slightly different shade of color.

Does this sound like what's happening?

If this is the case try setting your rendering intents to this:

RENDERING INTENT:
Image: Relative Colorimetric
Vector: Relative Colorimetric

With this both elements will be rendered the same and 90% of the time this eliminates that problem.

This is assuming obviously that this is indeed the problem you're having. Let me know!

----
Scott Manwaring / Administrator
ONYXTalk.com - Peer to Peer Support & Discussion

[jbingaman]

Thanks Scott...I'll look into this. What you described has happened before so this may be the ticket.

Thanks to you also Leonard! I wanted to upload the file, but it's too large.

We'll check this out and reply accordingly.

[leonardr]

Scott - all drop shadows created by Adobe applications are vector-based, not raster. The only time you'd end up with raster effects is if you EXPLICITLY CHOOSE the Raster Effects menu items from Illustrator (so that implies that you know what you are doing) or that you are pre-flattening the PDF with lower quality settings.

Leonard

[jonkovach]

I am curious - can you take a screenshot of the problem in question, as you look at it in PreFlight?

What happens when you turn the Color Matching Table off in Onyx, then apply those settings in PreFlight? Does the problem go away? This is a workaround that we use, sometimes, if we can get away with turning the Pantone matching off.....

Jon

[viofems]

Are you viewing the pdf in Acrobat? Sounds like 'Overprint Preview' is on. Check it off – then see how the file looks.

[ScottyDoo]

I suppose to be more accurate I should really say that Onyx often times treats and/or interprets the drop shadow effects out of Illustrator like raster elements when the files is imported and are therefore they are rendered differently.