[TheForge] Trace corrosion & fingerprints (Re: Hobo Nickels)

[Mike Spencer]

Related only tangentially (if at all) to the hobo nickels:

Faint, invisible corrosion on metal left by fingerprints can be
resolved.

    The patterns of corrosion remain even after the surface has been
    cleaned, heated to 600C or even painted over. This means that traces
    of fingerprints stay on the metal long after the residue from a
    person's finger has gone.
    [snip]
    To visualise the patterns, Bond's technique involves passing 2500
    volts through the metal and sprinkling a fine conducting powder on
    it. While the electric field is applied, the powder sticks to the
    corroded areas.

More at:

http://www.guardian.co.uk/science/2008/jun/03/fingerprints.bullets?gusrc=rss


FWIW,
- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^