illustrator flattens existing layers when opened (pdf)

[Arkadiusz Jas32409061u0tg]

Illustrator version: 28.7.1

but it happened also in previous versions

[Ton Frederiks]

When editing an Illustrator file, always save as .ai

A pdf is not intended for editing.

If you want to save as PDF and also need to edit the Illustrator file, save a copy or make sure that the "Preserve Illustrator Editing Capabilities" option is checked.

Just saving as PDF without that option will remove layers and other Illustrator options.

[Arkadiusz Jas32409061u0tg]

We also need pdf with layers for client.

The problem does not affect all PDF files. So far I have only had 3 cases. I have been using illustrator for many years and this has never happened to me. Im always using default settings for saving as PDF

[Ton Frederiks]

I guess you mean layers in the PDF file.

These are only top layers that are converted to what is called PDF layers, but what are actually ways of grouping content: OCG, Optional Content Groups. 

These will not be there when a PDF without Illustrator Editing Capabilities is opened.

It could be that your file has become corrupted and only the PDF part is opened.

Where do you save your files?

[Arkadiusz Jas32409061u0tg]

I save all files on my company's network drives.

This is definitely some bug or some problem with random pdfs

[Ton Frederiks]

Illustrator does not always work well with network drives.

Try if saving local and copying the saved file to the network drive helps.

[Ton Frederiks]

According to this help file "Adobe Technical Support only supports using Illustrator on a local hard disk. It's difficult to re-create or accurately identify network- and peripheral-configuration problems."

https://helpx.adobe.com/illustrator/kb/illustrator-support-networks-removable-media.html

[Arkadiusz Jas32409061u0tg]

I copied the problematic files to the local drive. Unfortunately it didn't help. If we open the same PDF with Adobe Acrobat Pro, all layers are visible. Illustrator only shows one layer

[Ton Frederiks]

Illustrator only reads it's own layers from the Illustrator part of the file.

Acrobat layers are not really layers, but groups of elements (a single object could be part of many Acrobat "Layers").

[Arkadiusz Jas32409061u0tg]

I'm not sure you understood me correctly.
The pdf file that I opened with Acrobat pro was exported from Illustrator. Later, when I opened the same file with Illustrator, all the layers were merged.
I didn't do any editing with Acrobat Pro. Some printing houses only use PDF files with layers and color profiles.

[Arkadiusz Jas32409061u0tg]

Please look at this screenshot. This is the same file (created in Illustrator and exported to PDF) opened in Acrobat and Illustrator.
Acrobat shows all the layers I have created. Illustrator shows only 1 merged layer

[Monika Gause]

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@Arkadiusz Jas32409061u0tg  schrieb:

Acrobat shows all the layers I have created. Illustrator shows only 1 merged layer

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Acrobat layers are not the same as Illustrator layers. Illutrator cannot read PDF layers. It can only read its own layers. If you do not save your PDF "Illutrator editable" OR if saving goes wrong and the file goes corrupt, then your layers are gone.

Please watch this about Illustrator files: https://youtu.be/IpDh8Y7q8yE 

[Arkadiusz Jas32409061u0tg]

Now you are teaching me how to save pdf files....

I'm doing this for 10 years working as graphic designer, Everyhting works fine until last month.

I just trying to tell you that Illustrator corrupts files that it had previously exported

[Ton Frederiks]

That is because something went wrong when saving the file.

The Illustrator layers were converted to Acrobat "Layers", Optional Content Groups.

But when the file was reopened in Illustrator, the PDF part was opened. Either because the file was saved without Illustrator Editing Capabilities or because the file became corrupted when saved over a network.

[Arkadiusz Jas32409061u0tg]

Let me put it to you in a different way.
The PDF I was opening is from 2022 (created by Illustrator 2022). When I opened it a year ago with the Illustrator 2023 version, everything was fine.
This pdf has not been modified.
It's not a matter of wrong file saving.

[Monika Gause]

If Illustrator doesn't find an AI file inside the PDF, it will open the PDF. And Illustrator cannot use PDF layers. Illustrator can only use its own layers.

What happened to your disk all these years? Wouldn't be the first file I've seen to get corrupted. Yes, this includes my own files. Copying them from one drive to another can corrupt them as can a recovery operation. And a lot of other things.

[Ton Frederiks]

Monika described exactly what could have happened. Anyway, you are openin somehow the pdf part and not the .ai part.