InDesign can not open files saved by later versions of the application.
This has been a source of a lot of grumbling over the years. I’ve heard all kinds of silly theories as to why this is so — including one that Adobe does this on purpose to “force” you to upgrade. Conspiracy theories are exciting and everything, but there’s really no conspiracies related to InDesign…
This issue will be brought to the forefront once again with the release of InDesign CS5.5. InDesign CS5 will not be able to open InDesign CS5.5 files. Here’s an explanation as to why:
The InDesign file format is in reality one of a database, and InDesign is a (very complex) transactional database application. Every action in InDesign is a database transaction and all these transactions are saved as a database file for InDesign to be able to read. The fact that InDesign works this way allows for many of its advanced features such as unlimited undo and its almost flawless file recovery. (Interestingly enough a lot of “fluff” is saved in the file resulting from previous transactions which get cleared out by doing a “save-as”.)
Anyone who works with databases knows how important it is to get the database structure correct from the start. Once a database has a structure, it’s very hard to change things later on. Any major changes that might be made can be very difficult to implement and inefficient to boot. InDesign suffers from the same issues as standard databases, and if InDesign was locked into a non-changeable database structure, it would make it very difficult to efficiently add some of the new features and make certain application optimizations impossible.
To solve this problem, each version of InDesign has its own database structure, so it can be properly optimized. Newer versions can read the older database format because the format existed when the newer version was created, and the older format is converted to the newer one when the file is opened. Older versions can’t be expected to read a database format which did not exist when the application was released.
But CS5.5 is just a “dot update”.
Yes. Adobe is not marketing CS5.5 as a “full version”, and that’s because it’s targeting a specific market area (digital publishing), but there were some serious work done in InDesign to enable some of the new features which required structural changes.
What’s Adobe doing to make our lives easier?
Adobe originally create INX (InDesign Exchange format) for back-saving, but it turned out to be less than ideal for its purposes. It was not really human readable, and InDesign 2.0 couldn’t read it at all. It was not really editable, and it was more or less useless for anything other than InDesign (CS and later) reading a document exported as INX up to one version back.
With CS4, Adobe took INX back to the drawing boards and came up with IDML (InDesign Markup Language). IDML (as well as its sister ICML and IDMS formats) is human-readable xml. The properties match those used by scripting, and the files can even be created from scratch. Additionally, Adobe has made every effort to make IDML truly backwards compatible. New features are simply additional XML tags which are ignored by previous versions, and with the release of InDesign CS5.5 it is finally possible to back-save two versions. IDML files saved by CS5.5 can be opened by CS4 with only the “standard” issues that are to be expected when saving back to a previous version with less features than the one which created the file. You can expect there to be text reflow, and new features used will be badly mangled, but the content of the file and basic features should all be preserved.
We have every reason to assume that this pattern will be continued in future versions of InDesign, so despite the fact that CS5.5 files cannot be opened in CS5, we finally have a solution to the back-save problem that people have been complaining about for years.
Long live IDML!Tags: back-save, CS5.5, IDML, InDesign