Thanks to Dan Bowman for reminding me of this: Due to a bug in the compression engine in some Xerox photocopiers, copies aren’t necessarily identical from generation to generation. For example, it’s very easy for a “6” to become an “8.” Not good.
There was a Dilbert cartoon where the pointy-haired boss, to Wally’s chagrin, proofread photocopies. Suddenly that joke doesn’t seem quite so funny.
As cheap as storage is, I have a hard time understanding why copiers use lossy compression. There are good lossless compression algorithms out there that ensure each copy will be as close to identical as the scanning hardware permits. And I understand the desirability of image enhancement technology–it would make fuzzy documents easier to read–but such a feature should be optional, so as to avoid situations like this.
If you use Xerox equipment, be sure to bug your rep for a fix. Early and often.