Companion formats

Companion formats reuse IDML's element names outside the package: a snippet of page items, a single InCopy story, an assignment of stories to editors.

In short InDesign and InCopy write a few files for jobs smaller than exporting a whole document. An InDesign snippet (.idms) holds a selection of page items with the styles and colours they need. An InCopy story (.icml) holds the text of one story. An assignment (.icma) groups stories for an editor. Each is a single XML file using the elements you know from the package (page items, stories, styles and colours), with no ZIP container and no design map. A library (.indl) is related by use, not by format: it is InDesign's own file for keeping reusable items, not an XML file.

Most of this reference describes the IDML package: a ZIP archive that opens at a design map and contains a whole document. The companion formats carry a slice of a document for a narrower job: a piece of layout to reuse, a story to edit away from the layout, a set of stories to hand to one person.

• The companion formatseach format as a fact: what it holds, how it is marked, how it differs from a package.
• When each appliesthe workflows that produce them, and how each relates back to the package.

What they share, and what they lack

Each companion file is one XML document, with an <?aid ?> processing instruction at its top saying what kind of file it is. What none of them has is the design map: the root part that names a document's spreads and stories and holds its document-wide settings. A snippet is completed by the document it is placed into; a story file by the frames it flows back into.

In Paged: the IDML importer opens .idml packages, and .paged containers, which are IDML packages too. It has no reader for .idms, .icml or .icma files.

Planned

Frequently asked questions

What are IDML companion formats? Files that use IDML's XML vocabulary without being a document package: InDesign snippets (.idms), InCopy story files (.icml) and InCopy assignment files (.icma). Each is a single XML file written for a narrower job than a whole document.

Is a snippet a small IDML document? No. A snippet is a fragment: page items and the resources they need, with no design map. It becomes part of a document only when it is placed into one, and the host document then decides how incoming names that already exist are resolved.

Is an InDesign library an IDML file? No. A library (.indl) is InDesign's own file format for keeping reusable items. Its items behave like snippets when you place them, but the library file itself is not XML.

Can Paged open a snippet or an InCopy file? No. Paged's IDML importer reads .idml packages and .paged containers only.