Rendering issues PDF from Indesign / Kodak Preps

[Phideaux]

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.

 

[Dov Isaacs]

Some thoughts, although you may not like all that I have to say :

(1) The PDF file you attached does indeed show text with an actual gradient overlaying a raster image. I can't see exactly what the problem is.

(2) One of the reasons I cannot discern the problem is that unless you provide the underlying digital assets (i.e., the InDesign document and the placed imagery), one cannot tell whether the exported PDF from InDesign is “correct” or not. For that matter, you didn't even provide the PDF file that was directly exported from InDesign, but rather a PDF file that went through Creo Normalizer JTP, whatever that is. The Creo brand name hasn't been used in many years, possibly over 15 years or more. Exactly what did you process the InDesign-exported PDF file with? Back in the day prior to Kodak's acquisition of Creo and the use of the Adobe PDF Print Engine as the actual internal RIP, Creo's Prinergy software used to ruin perfectly fine PDF files via a so-called “normalization” process that converted the submitted PDF file to PostScript and then converted the file back to PDF. Kodak's products no longer do that!

(3) PDF/X-1a was a wonderful workflow for 20th century print workflows. PDF workflows that don't support live transparency and ICC color management are inherently “problematic” for any content that has any colorants other than process CMYK and/or any transparency. There was a very good reason why we created the PDF/X-4 standard that supports live transparency, ICC color management, etc. Both major RIP suppliers, Adobe and Global Graphics, as well as modern print trade associations most strongly recommend PDF/X-4-based print workflows.

- Dov

 

[prepressdork]

Interesting. When I inspected that PDF with Pitstop, it shows as though the text is still colored with the gradient. What’s also interesting is that if you look at the ‘OOP’ in ‘VERLOOP’, the color within those letters starts to get darker. It’s as though the center point of the gradient got moved further to the right (even though Pitstop seems to suggest otherwise).

 

[Phideaux]

Well, the main issue isn’t that InDesign struggles with flattening certain regions — I’ve seen that before, especially when designers combine vectors with pixel-based elements and use transparency or blend modes. In most cases, I end up using Acrobat and PitStop to fix those issues. Hopefully, Adobe will eventually address them.

But in this particular case, the problem was that my client wasn’t aware that InDesign doesn’t flatten the region in the way you might expect — even when exporting to PDF/X-1a with a PSO Uncoated profile. And honestly, I wasn’t aware of it either until the job had already been printed and delivered. The issue only became visible when the PDF was processed in Preps. At that stage, I’m usually focused on technical details rather than checking the design itself. Often, that’s also the point where a colleague takes over to produce the printing plates.

In fact, I didn’t even realize that Preps modifies the actual PDF — I always thought it just positioned the file without altering anything.

Maybe this was just a case of bad luck, but I really don’t like that kind of outcome. I want a reasonable explanation and a better understanding of these issues — so I can prevent them in the future.

 

[Phideaux]

Update:
I tested a similar issue using Serif Affinity Publisher, and surprisingly, Affinity automatically converts the text with the gradient into outlines — without requiring any special settings. That said, I did notice there’s an option to rasterize unsupported properties.

 

[Dov Isaacs]

I opened your file.

Unless I am really missing something, there isn't any use of transparency at all in the InDesign source file and as such, no transparency to “flatten” in any way.

Perhaps you are really equating gradients with transparency? They aren't. Smooth-shaded gradients which you use in your “Testcase Verloop” text have nothing to do with transparency and are not “flattened” into anything else. Smooth-shaded gradient support is a native feature of PDF 1.3 (inherited from PostScript Language Level 3) and for that matter PDF/X-1a.

There is absolutely nothing that InDesign is doing wrong in exporting your document to PDF.

(What you are seeing in your printed result, I obviously cannot confirm. But on the screen in Acrobat Pro and printed directly from Acrobat Pro, I see no anomalies!)

- Dov

PS: @Phideaux, what Serif Affinity Publisher is doing is absolutely wrong!! There is no reasonable basis to convert text with gradients into “outlines” unless you love degrading output. PDF does in fact support filled text rendered with smooth-shaded gradient fills!!!!

 

[Phideaux]

Ok, I'm learning here ;-)

Dropbox-link

I'm sharing the file I received from my client — the original InDesign PDF — along with the PDF output generated by Kodak Preps.
This is the first time I've ever seen this issue occur in a Preps-generated PDF, which is why I tried to replicate it using a test file.
The issue only appears in files where actual text has a gradient applied to it; it does not occur when the text is outlined.

 

[tngcas]

We've run into similar issues with some of the programs that people are starting to use as they switch away from Adobe Creative Cloud.
Gradient effects around fonts or in the background of images are a problem.
One specific example is PDF files generated in Affinity seems to have a ton of gradient related rending problems that aren't usually detected by InDesign.

 

[Phideaux]

Another test without photo in background-link

This is also noticeable: when I remove the background photo, the gradient on the text element displays correctly.
It seems the issue might be caused by a combination of the text element, the applied gradient, and the pixel-based image underneath. Could it be that this interaction is causing the rendering problem?