About Microsoft Document Imaging Format (MDI)

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Microsoft Office Document Imaging uses Microsoft Document Imaging Format (MDI), a file format based on the Tagged Image File Format (TIFF) (Tagged Image File Format (TIFF): A high-resolution, tag-based graphics format. TIFF is used for the universal interchange of digital graphics.) that is designed to store images by page layout. In Office Document Imaging, you can open and save files in the MDI format as well as the Tagged Image File Format (TIFF) (Tagged Image File Format (TIFF): A high-resolution, tag-based graphics format. TIFF is used for the universal interchange of digital graphics.) format. Both formats are capable of storing text recognized by optical character recognition (OCR) (OCR: Translates images of text, such as scanned documents, into actual text characters. Also known as text recognition.) along with images.

File format comparison

While you can open and edit TIFF files created with Office Document Imaging by using many other graphics applications, MDI files can only be opened or edited in Office Document Imaging. If you are going to share files with people who are using Office Document Imaging 2002, or another document imaging program, save your files in TIFF format for compatibility.

In general, images that are saved in the MDI file format take up less disk space than the same images saved as TIFF files. The image quality of an image saved in the MDI file format is comparable to that of the same image saved in TIFF.

File format selection

There are different times within Office Document Imaging when you can choose the file format (either MDI with an .mdi extension or TIFF with a .tif extension) for your document:

Scanning a document     The scanning preset you choose determines the format the scanned document is saved in. You can create your own scanning preset or edit an existing preset to change the file format.

Saving a document     You can select the file format in the Save as type list in the Save As dialog box when you save a file.

Importing a document     The File Import preferences button on the Other tab in the Options dialog box (Tools menu) allows you to select the default file format for documents that you import from other programs.

ShowTechnical details

Office Document Imaging creates MDI files in these formats:

  • Monochrome One bit per pixel, MODI BW compression
  • Grayscale 8 bits per pixel, MODI Color compression
  • Color 24 bits RGB, MODI Color compression

Office Document Imaging supports:

  • All compression types listed in the TIFF 6.0 specification.
  • Different compression types for each page of a multi-page document.
  • TIFF images with 1-bit, 4-bit, 8-bit, or 24-bit color depth (both palette and non-palette).
  • MDI images with 1-bit, 8-bit, or 24-bit color depth.
  • RGB and CMYK color spaces.
  • Tiled images.

Office Document Imaging does not support:

  • YCbCr color space, except when the image is JPEG.
  • CIE Lab color space.
  • Images with more than five samples per pixel, or a sample size larger than 32 bits.
  • Images in Planar format.