[PADG:926] RE: Question on patinas

["Van Norman, Matthew" <mvannorman@xxxxxxxxxxxxxxxxxxxxxx>]

I'm not sure if this will be particularly helpful, but patination (or
tarnish) of metal is caused primarily by exposure to oxygen. This process is
usually also moderated by the amount of light and moisture to which the
metal is exposed. I suspect the relative amounts of these factors, as well
as various impurities within the metal itself, account for the different
colors you're seeing.

Assuming you want to reduce the amount of patination on your silver medals,
you would want to keep them away from air and light as much as possible. But
I suspect you have these medals on display, so you may want to think about
some form of varnish or wax to at least limit the silver's exposure to
oxygen and moisture.


Matthew D. Van Norman
CSUF Pollak Library
Periodical Services


-----Original Message-----
From: Graeme Marfleet [mailto:GraemeM@xxxxxxxxxxxxxxxxxxx]
Sent: Tuesday, February 22, 2000 6:48 PM
To: 'PADG Discussion list'
Subject: [PADG:917] Question on patinas


Hello,

I'm looking for information on the possible causes of different coloured
patinas on sterling silver medals.

Is this the appropriate list for such a question ?
If not will somebody please point me in the right direction.

Thanks in anticipation

Graeme Marfleet