What is IDML? What’s a .idml File? Adobe InDesign Markup Language?

What Is IDML?

Per the Adobe InDesign Markup Language Cookbook, “IDML is an XML-based format for representing InDesign content. Essentially, it is a major revision of INX, InDesign’s previous XML-based file format – something that can be reasonably assembled and disassembled by a competent programmer.”
(Source: http://wwwimages.adobe.com/content/dam/acom/en/devnet/indesign/sdk/cs6/idml/idml-cookbook.pdf)
IDML stands for InDesign Markup Language, which was developed by Olav Martin Kvern, Adobe staffer and co-author (with David Blatner and Bob Bringhurst) of the “Real World Adobe InDesign” book series.

Adobe’s InDesign application is among a variety of applications that are available to Creative Cloud subscription holders. With InDesign, users can create and modify documents, graphics, images, visual components, and other document items.

Export IDML

IDML (.idml) files are InDesign Markup Language documents. InDesign Markup Language is the interchange format for InDesign (.indd) documents. The .idml file extension, associated with IDML files, designates the proprietary document file format created by Adobe Systems.

An IDML file represents the objects and properties of an Adobe InDesign (.indd) file, as XML elements and attributes. The IDML document contains meta data, formatting attributes, layout properties and multimedia content objects.

An IDML document can be an individual file or a set of files, packaged in a .zip folder. Files are grouped as preferences, spreads, and stories, in the ZIP folder, to simplify the search for items contained in the files.

How Is IDML Used?

IDML is designed for use in InDesign, InCopy, InDesign Server, and other Adobe applications. Users can add XML tags to an IDML file and, when an IDML file is opened within InDesign, the application converts the tags to objects.

The .idml file format supports applications for multi-media content creation and editing. With an XML representation in the .idml file format, an InDesign document can be created, opened and edited, by using the Adobe InDesign application or third-party software, such as IDMarkz. Here is a video about IDML:

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In this Markzware video, David Dilling answers questions, like “What is IDML? What’s a .idml file? Adobe InDesign Markup Language? What are IDML file uses? What’s the benefit of IDML?” The IDMarkz app by Markzware can export InDesign files as IDML and as many other file types. This video can also be viewed on YouTube at

[Start of Transcript]
Hi, everybody. David Dilling for Markzware, here. I Hate Living in Apartments (YouTube user) had a great “what the heck is an InDesign IDML used for? what is the benefit of it?”

Well, it’s a good question, I Hate Living in Apartments. I’ve often wondered, outside of real InDesign geeks, how many knew, or know, what IDML is?

It’s the InDesign Markup Language from Adobe. Adobe defines IDML as an XML-based format for representing InDesign content.

IDML effectively allows for backwards compatibility with newer versions of Adobe InDesign. It’s also a great way to back up your file.

Let me show you how it works. In InDesign, you can do a File > Export and choose from various formats, including InDesign Markup, or IDML. You can also do a File > Save As, in modern versions of InDesign, like this is, here, CC 2020, and also choose for IDML, where they’ve added the “InDesign CS4 or later,” to make it clearer, the benefits of IDML.

The .idml is like a wrapper around your content, zipped up and inside this container. If we take a look at it, like under a microscope, so to speak, you’ll see that, inside the XML, or the IDML, you’ll get all the attributes and the resources, like fonts, graphics, preferences, styles, etc.

Does an IDML contain the images? The linked assets? No, it does not contain the linked images. Yes, it will include the embedded images.

The “Export” button, to export InDesign files to IDML, is in the top left of the main IDMarkz window. Notice the scrolling thumbnails and document information panel, to the right.

I just want to break in here, again, just for a very important note. Embedding images will bloat your InDesign file, greatly. And will also bloat the resulting IDML.

We have other videos on why it’s better to link, and not embed, images. It goes deeper than you think. It can also corrupt your InDesign file. I’m not kidding. We get a lot of these bad files in.

Alright, so, that’s what IDML is, from Adobe. Now, for the fun part. Nowadays, IDML is being used by other third parties, for instance, QuarkXPress and the new Affinity Publisher > Import IDML Files. The problem is you need InDesign, and that’s where we, here at Markzware, can help out.

We have the new IDMarkz application, a stand-alone macOS application, which allows you to preview and convert InDesign files, without the need for Adobe Creative Cloud.

To preview is very easy. You just drag & drop an InDesign file on the interface and you get a nice, high-resolution preview of the file.

From there, you can export, and there are various details or options available, for exporting, including IDML, but also PDF and PNG. And, at last, you can convert.

You can convert automatically to the IDML, to InDesign, Quark, or Affinity Publisher, like you see, here, is happening on screen. With a click, you can get that huge InDesign document, this Dealer Sales Guide, right up in Affinity Publisher.

Affinity Publisher
Affinity Publisher logo

Go over to markzware.com, today, if you want more information on how you can preview, export, and convert your Adobe InDesign content. IDMarkz is for InDesign users and viewers, alike, and those dabbling in other areas, like Affinity Publisher.

Thank you, everybody. That’s what IDML is, and a little bit of bonus material on how you can use IDML in other DTP applications, and how IDMarkz can help you achieve this.

By the way, IDMarkz is completely free, for just previewing, so, check it out, today, like we mentioned, on markzware.com. Alright, everybody, have a great day! David Dilling, for Markzware, signing off.
[End of Transcript]

Markzware develops software for Adobe InDesign users and non-users, as well as for users of many other page layout applications for desktop publishing. Markzware’s IDMarkz helps to preview and convert InDesign files to IDML, QuarkXPress, Affinity Publisher, Illustrator, Acrobat PDF, PNG, JPEG, TIFF, earlier InDesign versions, and other popular file formats.

IDMarkz Benefits

• enables fast InDesign file viewing, on the macOS platform
• saves additional costs of expensive InDesign file apps
• allows freedom from Creative Cloud subscriptions

“The IDML format seems to be accepted by quite a lot of web authoring tools. So, that’s one route, to do it, that seemed to be quite a stable format, the InDesign Markup Language file format.”
– Paul Lindström, Technical Editor, Journalist & Consultant, Digital Dots
Source: https://www.youtube.com/watch?v=-jVR2u8e1h8

IDML Export feature in the IDMarkz application by Markzware

How to Export an InDesign File as IDML:

• Drag & drop your file onto the IDMarkz window, in the “Drag and drop files here” section.
• Click on Export icon in the top left of the IDMarkz viewing window.
• Select the desired file format.

IDMarkz Features

• View, in IDMarkz, the InDesign version in which your file was created, the dates when it was created and modified, and the number of:
– pages or spreads
– fonts used in the file
– colors used in the file
– images used in the file
– Stories in the file
• Zoom in and out of previews
• Drag a thumbnail out of the preview or thumbnail areas and create an image of the page
• Automate features that support InDesign, Acrobat plus other apps
• Export your file in IDML, PNG, TIFF, JPEG and GIF formats
• Export a PDF with editable text

IDMarkz Automation Preferences [Light Theme]
IDMarkz Automation Preferences, to automate the export of InDesign files as IDML.

Convert InDesign CS2 through InDesign 2020 Files to:

• earlier InDesign versions
• QuarkXPress
• Affinity Publisher
• Acrobat
• Illustrator
• PDF with editable text

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Buy IDMarkz, Today!

You can buy Markzware’s low-cost IDMarkz Mac Subscription, which includes IDMarkz updates throughout your 12-month subscription term. For more information, please visit the IDMarkz page. Additional Markzware products are available via the Products page.

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What is IDML? What’s a .idml File? Adobe InDesign Markup Language?

Title: What is IDML? What’s a .idml File? Adobe InDesign Markup Language?
Published on: March 5, 2020
David Dilling

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