MMR Compression (Modified Modified READ)
Definition
An ITU-T fax compression standard (T.6) used in high-quality fax transmission modes; produces characteristic compression artefacts visible in fine character strokes of received fax documents, distinguishing them from photocopies.
- Standard
- ITU-T T.6
- Domain
- High-quality fax transmission compression
- Forensic use
- Distinguishing received faxes from photocopies
- Visible artefact
- Compression distortion in fine character strokes
Common questions
Why does MMR compression leave a visible trace on a printed fax page?+
The two-dimensional coding scheme approximates scanned lines by referencing changes from the previous line, and this run-length approximation subtly distorts thin strokes and diagonal edges in a way plain photocopying does not.
Is the compression artefact alone enough to prove a document was faxed?+
It is strong supporting evidence, but examiners usually corroborate it with header lines, timestamps, and other fax-transmission markings rather than relying on the compression artefact in isolation.
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