Indesign flatten transparencies

[M.E.310814321c2q]

Hello. Sorry to bother y'all again.

In the Export Adobe PDF window, compression, which setting should be chosen for flattening transparencies:
PDF/X-1a:2001
PDF/X-1a:2003
PDF/X - 3:2002
PDF/X - 3:2003
PDF/X - 4:2010

[Willi Adelberger]

All except X-4 flatten transparency. 
Why do you want to flatten transparency?

[M.E.310814321c2q]

Hi.
In order to upload, rather export and then upload my book as a PDF,
the printer wants my images flattened.
I'm guessing or I understand that transparencies have multiple layers
and if all these layers are embedded (also what they want), then the file
is
way too large for them to handle, in some way I don't understand.

This is what the printer sent back to me. Flatten your transparencies.

Thus, I am not sure which choice to make in the window or list actually,
that I put into my post.
I have embedded my fonts, my images but they would not accept it until I
have done this.

I hope I was clear in my response to you.
Most of this is way over my head.

Cheers

[Dave Creamer of IDEAS · Accepted solution]

When you make your PDF/X-1 or 3, everything will be flattened. Be sure to select High Quality for flattening. 

You don't have to worry about layers in Photoshop or Illustrator files. If you are concerned about InDesign layers, simply turn off the "Create Acrobat Layers" option when exporting to PDF. 

PDF/X-1 flattens transparancy and converts colors to CMYK and spot.

PDF/X-3 flattens transparancy buts does not convert color.

PDF/X-4 does NOT flatten transparency or convert color. 

[M.E.310814321c2q]

Wow!
Thank you so much for such a clear and detailed message.
I feel like I have learned more as well.

Just hope I am able to retain it.

Again, thanks

[Willi Adelberger]

It is a diffeerence between what the printer wants and what is good to import to InDesign. Even if the Printer requires PDF/X-1a or 3, import PDF/X-4. Import and Export may have different standards.

[rob day]

Just hope I am able to retain it.

Also, when transparency will be flattened, Advanced>Transparency Flattener Preset: becomes enabled

[Willi Adelberger]

When you place images or other files into InDesign leave transparency and layers alive! So you can use layer comps and only so, the appearance will not change. When you import PDFs, use always PDF/X-4. 

Flattening sould only be done at the end. 

[Dave Creamer of IDEAS]

I believe the image layers will be flattened in the PDF. Transparency would stay live in X-4. 

I would not say "use always PDF/X-4". I would depend on what the printer asks for. While X-4 would be the current ideal, it's not always possible. 

[M.E.310814321c2q]

Hi.
If exporting to a PDF automatically flattens transparencies,
then why do you think I have been told after exporting to a printer (as a
PDF)
to flatten my transparencies?

So, X-4 does not do this I'm guessing.
Still unsure as to what choice I should make to flatten them.

thanks

[Dave Creamer of IDEAS]

Ask the printer if they want PDF/X. If they do, ask what version. 

If they don't know what PDF/X is, run!