Rendering Issues PDF from Indesign

[stefan_6324]

I discovered an issue with a PDF file exported from InDesign. The document contained a text object with a gradient, partially overlaying a photo. So essentially, a text element with a transparent effect placed on top of a pixel-based image.

The PDF was exported using the PDF/X-1a preset, so I expected the file to be fully flattened. Visually, the file looked fine, and PitStop Preflight reported no issues. The next step was to place the file into Kodak Preps for imposition for offset printing. At that stage, everything still appeared correct.

However, the imposed PDF exported from Preps showed the text object without the gradient. Instead, the text was filled with just one of the gradient colors. After testing and replicating the issue, I found that it did not occur if I flattened the PDF a second time in Acrobat, or if I removed the photo underneath the affected object. Another workaround was converting the text to outlines.

My conclusion is that a text object with a gradient over a photo is too complex for InDesign to properly flatten during export.

But here’s the puzzle:

Why doesn’t InDesign warn me during export that certain complex regions might not flatten correctly?
Does this sound familiar to anyone? I haven’t found much information online from others who’ve encountered this or similar issues.

[kglad]

in the future, to find the best place to post your message, use the list here, https://community.adobe.com/

p.s. i don't think the adobe website, and forums in particular, are easy to navigate, so don't spend a lot of time searching that forum list. do your best and we'll move the post (like this one has already been moved) if it helps you get responses.

<"moved from cc desktop bugs">

[Willi Adelberger]

Use PDF/ -4 instead of 

[rob day]

The next step was to place the file into Kodak Preps for imposition for offset printing

Hi @stefan_6324 , As I’m sure you know the PDF/X-1a standard does not allow any transparency, so it seems like the transparency problem is being introduced by the Kodak Preps software. The 4-up imposition is pretty simple—have you tried a manual step and repeat in InDesign and outputting the 4-up PDF without the Kodak software? Or as @Willi Adelberger suggests feed a PDF/X-4 to the Kodak software and let the flattening happen there?

[stefan_6324]

The file I uploaded was not the actual file from my customer, but a test file I created to replicate the issue. I designed it to closely match the customer's file, exported it, and followed all the necessary steps, including imposing it in Preps.

The key issue is that InDesign appears to have problems with text elements that involve transparency and overlapping. However, there are no visible signs of this issue until the PDF is rendered in Preps. 

In the real-life scenario: I received a PDF from a customer who was unaware of the problem and cannot be held responsible at that point. We only noticed the issue when we were preparing the offset plates for printing—or sometimes not at all, since at that stage our focus is more on technical details like color bars, cut lines, and registration marks.

I wish I had been alerted to the issue earlier in the process.

[stefan_6324]

Edit:
I tested the PDF/X-4 export, but the result was the same. In Preps it's not possible to specify a particular PDF version for export. I verified the output using Acrobat Preflight, and after exporting from Preps, the file no longer complies with the PDF/X-4 standard. This suggests that Preps may be handling the PDF content in a way that breaks compatibility.

[rob day]

I tested the PDF/X-4 export, but the result was the same.

When you export to PDF/X-1a what Transparency Flattener Preset are you using—the default [High Resolution]? Have you tried a custom preset? The text can be converted to outlines in the preset. Strange that only one of the 4 repeats has the problem—that seems to indicate it's being introduced with the imposition.

[stefan_6324]

The one with the problem is the version with "live"-text, the others are outlinetext and/or flattend through Acrobat.

For the transparency flattener, I use "High resolution" or "GWG_2400_v2012".

[rob day]

 the others are outlinetext and/or flattend through Acrobat.

What are the settings for GWG_2400_v2012? You could convert text to outlines in the preset

[stefan_6324]

I understand all the solutions you bring in, but the bottom line is:
How can I discover these flaws in a PDF document sent to me by a client. We don't have these issues in our own designs. 
Or: how can I avoid not noticing these issues.
Thanks for your input on this issue. 👍🏻

[reproo2773183 · Accepted solution]

PDF/X-1a doesn't allow transparency so if there was transparency in the text it would be turned to pixels not outline.

PDF/X-1a does allow DeviceN and overprint, if you try to convert to cmyk down the line it could cause something like you are experiencing. InDesign is quite good at doing fake transparency DeviceN and Overprint and I don't beleive you can control the behaviour. The RIP needs to simulate the overprint when rendering and create new object. I use Preps to do my impositions but print to jdf and let Prinergy do the rendering. Its likely that Preps has much more basic understanding of PDF. 

I do see problems like this occasionally when imposing files on my Fiery imposition program, my fix is to use preps and then prinergy to make an imposed pdf, then print direct from that on the Fiery. One of the things too look out for is complicated use of "Shadings" inside the pdfs, often on Fiery imposition pdfs they'll affect other station positions in a step and repeat.

[Brad @ Roaring Mouse]

Flattening has nothing to do with the issue. In fact, there was no flattening necessary in this file. (You can see this if you open it in Illustrator). Your text object has no effect applied that requires it, and gradations themselves are native objects that don't require flattening.

"However, the imposed PDF exported from Preps showed the text object without the gradient"

Well, actually, it IS there, it has "shifted" to the far right for some odd reason so only shows mostly the red end. You can also see this if you open the Preps file in Illustrator.

I'm curious why you're are saving as PDF/X-1a anyway. Your Preps export is well above that so there should be no reason to save any less than 1.5 (In fact Kodak recommends no less than that. Even when I worked with Preps years ago, we rarely needed to flatten a PDF and only as a troubleshooting attempt.

"Why doesn’t InDesign warn me during export that certain complex regions might not flatten correctly?"

Nothing to warn about. As I said, no flattening occurred. The PDF was fine.

[stefan_6324]

Thanks for your reply.

The files I uploaded were test cases created to replicate a file I received from a client. The original file from the client was a PDF with the same specifications.

In fact, I tested various scenarios using different PDF versions and even different versions of Preps. In all cases, the outcome was the same.

At this point, the only viable solution is to be more mindful of these tricky situations and, in cases like this, perform a flattening action on the specific page using Acrobat.