In article ,
"R.W. Behan" wrote:

Can't tell you about archival qualities, Greg. I have some prints that are
probably 5 years old now with no sign of discoloration. I suspect this
stuff is as permanent as Spot Tone, anyway.

It very well could be as long lasting, upon searching I found two
companies make "Spot pen(s)" Marshalls and Tetenal.

--
LF Website @ http://members.verizon.net/~gregoryblank

"To announce that there must be no criticism of the President,
or that we are to stand by the President, right or wrong,
is not only unpatriotic and servile, but is morally treasonable
to the American public."--Theodore Roosevelt, May 7, 1918