Bloated files when using linked images with transparency masks

[Amdival]

When I use a linked file with a transparency mask, the file is bloated. It's as if Illustrator is not treating the file as being linked.

Illustator has not always bewhaved this way. Sometime in the last few years this bug has arisen.

[Monika Gause]

Do you save with "PDF compatibility" turned on? In that case Illustrator saves a full PDF into your file. In a PDF linked files are always embedded.

This has been the case since at least version CS1. Maybe you just saved without "PDF compatibility"

[Amdival]

Thanks for the response!
 If I uncheck "PDF compatibility" it fixes the issue [for AI files], the problem still persists though when saving as a PDF.

[Monika Gause]

There won't be linked files in a PDF. Never ever. They are always embedded.

Use PDF compression settings on them.

[Amdival]

That's not true. A compressed version of the file is embedded, but the linked file is not embedded. Think about the times you have tried to open an edited PDF and you got the "missing linked file" dialog.

I have made some ground in tracking down the issue though!
I am used to being able to control the compression for images when saving as PDF. It appears that when am image is being used in a transparency mask, Illustrator is not downsampling the image when asked to. I still have control over the Image Quality, but the downsampling options are doing nothing like they normally should.

[Amdival]

To touch on this some. PDF compression settings work only if the images are linked. Embed the images in the PDF, and all of those settings are useless; they do nothing.

[Monika Gause]

When saving an AI file, a PDF or an EPS, you actually often save 2 files in one.

Please watch this video to understand what is happening:

 https://youtu.be/IpDh8Y7q8yE

When you open a PDF or an EPS that has been saved in Illustrator, you will not open the PDF respectively the EPS part, but the embedded AI file.

In the AI part, the images are linked. In the PDF part, they are embedded. To the PDF part, the compression options are applied. When you save an AI file with "PDF compatibility", there are no compression options, so images won't be compressed. But they will still be embedded.

[Amdival]

I get what you are saying. I would reword it to say that Illustrator creates new images upon saving and embeds those newly created images in the PDF. The original linked images are not embedded.

Ultimately, I found where they problem is. How do I get this in the eyes of the developers so that they are aware of the issue?

[Monika Gause]

Please post bugs & feature requests to http://illustrator.uservoice.com

[Amdival]

"It's as if Illustrator is not treating the file as being linked."

^ From the original post. After more experimenting, yes, Illustrator is correctly treating the file as linked, BUT! The downsampling options in the compression section of the save dialog are not working.

[Amdival]

Reword the issue now that more troubleshooting has been done:

Issue:
When saving a document as a PDF, downsampling (under compression) in the save dialog does not work if images are part of a transparency mask.

How to recreate issue:
1. Open or create new document. Place a linked image. Make a rectangle. Create a trasnsparency mask using the placed image and the created rectangle. Save as a PDF. Under compression, apply downsampling.

2. For comparison, now release the mask and resave with same settings. The file sizes will be drastically different. The issue is more evident if the image is scaled up large in the document.