 This is in contrast to some other algorithms, which simply degrade into a blur, making the compression artifacts obvious.Since JBIG2 tries to match up similar-looking symbols, the numbers "6" and "8" may get replaced, for example.In 2013, various substitutions (including replacing "6" with "8") were reported to happen on many Xerox Workcentre photocopier and printer machines, where numbers printed on scanned (but not OCRed) documents could have potentially been altered.