heavy file size goes magicly light when saving to IDML file - why?

[danezeq]

It wen down from 151MB to 19MB.

Converting my project from .indd file to .idml file couases me to wonder if theres anyway to reduce the .indd file size (while leaving it as .indd file)

[Eric Dumas]

Hi,

This is a good point. IDML files are exchange files. To avoid compatibility issues, a lot of advanced features will not be included to retain only the core items of your document.

Which means it will be lighter but you could loose the possibility to edit some parts of your document.

To be as large as you said, your file must have the images embedded instead of linked. I think Adobe assumes we all have modern machine that can easily handle and store such large files.

[danezeq]

So there is no way to make a massive diet for indd files?

[Laubender]

https://forums.adobe.com/people/Eric+Dumas  wrote

Hi,

This is a good point. IDML files are exchange files. To avoid compatibility issues, a lot of advanced features will not be included to retain only the core items of your document.

Which means it will be lighter but you could loose the possibility to edit some parts of your document.

To be as large as you said, your file must have the images embedded instead of linked. I think Adobe assumes we all have modern machine that can easily handle and store such large files.

Hi Eric,

I don't think so.

IDML files exported will build a new file where nearly all properties of the exported document are written as XML statements so that InDesign can create a new document with all that statements from scratch. If done with the same version of InDesign, export to IDML and open from IDML, you should see no difference compared to the original InDesign document. Of course there are some bugs and some restrictions. One of the restrictions is that previews of placed and linked images and graphics are not saved with an IDML file.

The situation changes if you open the IDML file with a previous version of InDesign. Then features that are written to the file that are not present with a legacy version of InDesign will be ignored. And you likely will also see changes in text composition, because rules of composition of text might have changed in the newer version.

The little brother of IDML is IDMS, InDesign snippet files, that work with the same XML "language" for describing features, but omit anything that is document related. IDMS strictly focuses on objects on a spread. That mean IDMS has no idea of the setup of the document the file was exported from like page size, color settings and so on. IDMS is not only used for exported snippet files but also for saved assets with InDesign library files and ( partly ) for assets that are stored with Creative Cloud libraries.

Regards,
Uwe

[Klaas vT]

I would think that this has a lot to do with the fact that IDML does not include thumbnails of the images used! I don't think you can tell the INDD to not include thumbs... someone might know that.

[danezeq]

Is there anyway to unembed at once all files and convert them to links?

[Klaas vT]

Go to your links panel, select all, right click, select Unembed all instances

[Eugene Tyson]

Your indesign file is a bunch of code.

Saving to IDML changes it to an InDesign MarkUp Language, which only gives relevant code information.

Once you open the IDML in InDesign it rebuilds the file.

If opening in an older version of InDesign, the newer features that you may have used will be reduced back to their basics. For instance, if you used Span/Split columns, and opened the file in a version of InDesign without that version, you would see some strange layouts in those areas that need to be tidied up.

If opening in the same version of InDesign it should reopen as it was.

As the file is just a bunch of code - each time you save your InDesign file you are adding to that code, which in turn increases the file size. Even if only small amounts of changes.

It is saving other information in the background. You can view this information in the file Information - open an InDesign file and got to About InDesign and hold down the CMD/CTRL key and it will show you a file info dialog.

Each section contains quite a lot of information.

Roundtripping to IDML will remove a lot of that information - which is only miniscule - but shows that the file is rebuilt and non-essential code is now defunct and removed.

Which leads to smaller more efficient files.

It's also a good way to fix issues with a file that is behaving weirdly.