EPS with transparency is pixelated

[Winfried Reng]

Hi,

I have a question about EPS and PDF.
In one of my graphics there is a terminal with a semi-transparent foil.
When I create an EPS file and import this into FrameMaker and create a PDF (or when I convert the EPS directly to PDF), then the contour of the semi-transparent part is now pixelated.
When I create a PDF file from my vector graphics application, then the PDF is _not_ pixelated. Also when I import this PDF into FrameMaker and convert to PDF, the resulting PDF is not pixelated.

Does Acrobat Distiller change anything on an EPS file, when it converts it to PDF? So that I can find out, if this is a FrameMaker/Distiller issue or a problem of my graphics application.

Best regards

Winfried

[Bob_Niland]

Sounds like this is more of an opacity issue than one of transparency.

What version of FM, by the way? (and I don't recall when transparency support arrived)

You might try the EPS 4× scaling trick, to see if it has anything to do with the EPS preview/thumbnail image. In the EPS editor, re-declare (without scaling) the extents of the whole composition by 4×. Save as EPS. Import back into FM at 25% of former size. This will improve the resolution of the preview for sure, but what it does at Publish is the question.

Another thing to try is to save the EPS as PDF, and import that.

[Be.eM]

Hello Winfried,

this is a problem with the combination of pixel and vector graphics in apps like Illustrator or Indesign, which handle transparency correctly (or in a more modern way), and the limited abilities of the EPS format, which does not support real transparency (just like FM2019 and lower). When exporting such an image from FrameMaker, there's always transparency reduction applied, which creates "slices" of the image, while converting some of the vector content to pixels. In this case the "pixelation" you've mentioned happens along the borders of the non-transparent pixel image part.

If this can be solved (while still using the EPS format) depends on the kind of images which are combined and the kind of transparency which is desired. It's very difficult to solve on a multicolored background. I've been somewhat successful in a few cases by creating an underlying vector image which follows exactly the shape of the not-transparent part of the pixel image (e.g. from an alpha channel). Making this underlying image e.g. black allows a transparency reduction against a uniformly colored background, which avoids those brighter pixels creating that "pixelated" appearance. However, you get an outline instead, which may or may not disturb the desired appearance.

To tell you more (if possible anyway) I'd need to know more about the source files and the FrameMaker version, etc.

Bernd

[Winfried Reng]

Hi Bernd,

Thank you very much for your explanation.

My EPS does not have any pixel image. It consists only of a vector drawing. And one part covers others with transparency.

Did I understand you correctly that EPS cannot handle transparency.

Then the solution is simple: I will use PDF instead.

I only wanted to know, if there is anything wrong in a certain step of my EPS workflow.

Best regards

Winfried

[Be.eM]

Hello Winfried,

plain vector on vector transparency should work, as long as there are no other effects (like drop shadows or glow) involved. Transparency reduction with vector objects simply creates single (cut) vector objects, similar to some pathfinder results.

Bernd

[Matt S - Tech Comm Tools]

Hi Winfried, you mention Distiller...are you using Fm 2020 with the Publish feature? I ask because that PDF engine is better (and faster) than previous methods, and does not use Distiller.

Regardless, I've had issues in the past with EPS. It (often) contains a preview image that is bitmap, and there are quite a few "flavors" of EPS that might cause issues in conversion.

Importing an Illustrator AI file or a PDF are both better options than the grab bag that can be EPS.

[Winfried Reng]

Hi Matt, thank you very much for asking! Yes. I use FM 2020 and the Publish feature. Although I should make some more tests with and without Distiller.

Generally my EPS files are imported into FrameMaker very reliably. I would have liked to switch to SVG for all graphics, but often the font is changed. (There is e.g text on a PCB or terminal numbers.) Therefore SVG works only for about half of my graphics. Although the SVG import is now much better than some years ago.

Best regards

Winfried