Posted by Rob Moseley on May 09, 2004
That phrase keeps turning up like a bad penny..!
My sister brought up that saying after I sent her a couple of scans of 1870s tintypes of grt grandparents, etc.
She remembers hearing that in the mid 1940s in Massachusetts when a youngster. 'Not on your tintype' is used randomly quite often on the Internet as seen in Google initial search-returns, as well.
It could be that the saying might be ascribed, as earlier mentioned, with the same degree of permanence as one's life (not on your life), because the tintype or ferrotype was a very durable piece of portrait work and highly treasured by individuals and families - the likeness being as 'real' as the person imaged.