There are times when some transient documents are to be printed, but there is no printer available nearby. In the Microsoft Windows operating system, with its Office Suite, there is an option to store an image in a non-modifiable format for safe keeping or for printing later. The Microsoft Document Image file format (or the MDI file format) is the de facto format that provides these services within the Windows OS.
An MDI file extension is developed from the TIFF (Tagged Image File Format) extension and is thus basically a tag-based graphics format. It can be invoked in any Office Document for printing purposes (under the Microsoft Office Document Image Writer printer) and can also be opened my Microsoft Image Viewer for viewing purposes only. MDI files are read only, i.e. since they are tag-based they cannot be edited and are thus highly suited for being an incorruptible soft-copy of any printed document.
These MDI files can also be printed later if needed. Since MDI files are used for printing purposes, this file format is a very high resolution graphics format which finds special use in many offices worldwide. This file format specification is thus one of the few ubiquitous file formats that does not find much use at home.
To open MDI files, the most commonly used software is the same software that builds MDI file extensions in the first place – the Microsoft Office Document Imaging (Part of Microsoft Office 2003 suite). However, if you are stuck with an MDI file format and you do not have the necessary built-in software from Microsoft, there is a software called “MDI Viewer” that can be used to open this file format. This versatile software also allows for the printing of the contents of the MDI files.
MDI to PDF converters also exist, and these are freeware tools or add-ons that facilitate fast and easy conversion. To convert MDI into Microsoft Word’s DOC format, one may use OCR (Optical Character Recognition) software to convert the readable text into editable text.
It should be kept in mind that the Microsoft Office Document Imaging extension is not automatically installed in the newer versions of the Office suite (2007) and thus has to be manually installed for opening MDI files. This can be facilitated through the “Add or Remove programs” portion of the Control Panel, under the Microsoft Office Suite program!