PCB documentation (Score 4, Interesting)

For years I've used a scanner as a cheap way to
document mods to PCB's (printed circuit boards, not
Polychlorinated Biphenyls). Even the tiny labels
that sometimes appear on 0603 resistors are
readable, and it documents what's there, rather
than what I _think_ is there.

However: some scanners have better depth of field
than others. The ones which sweep a mirror under
the document, rather than sweeping the sensors
themselves, seem to have better depth of field.