compression

LZW

The dictionary algorithm used by GIF and classic TIFF.

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How LZW works

LZW builds a dictionary of repeated sequences as it reads. Its former patent encumbrance is the reason PNG exists.

Family
lossless
Introduced
1984

LZW scores

Deterministic scores calculated from the structured facts above. Identical facts always produce identical scores.

Overall score

83/100

  • Archiving score

    100
    • it is a current, actively maintained format
    • it is actively maintained and current

    Confidence 35% · evidence coverage 56%

  • Longevity score

    89
    • it is actively maintained and current
    • it is a current, actively maintained format
    • it occupies a niche corner of the ecosystem

    Confidence 37% · evidence coverage 75%

Compression used

Data quality

Every claim on this page is classified as a verified fact, a derived fact or an assumption.

Overall confidence
88%
Verification status
verified
Last reviewed
2026-08-03
Verified facts
2

2 classified claims backed by 1 source.

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Sources and review status

Review status: verified · confidence 90%

Last reviewed 2026-08-03 (revision 1).

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