This site the starting point for the penny black plating site, and the missing imprimatur database.

The Mulready Group However, you will need to register, in order for your registration to be approved,
please send me an email with your interest in this subject to stamps@ this web site.
Plating the Penny Black <--This is the largest archive of Penny Black images anywhere!
Missing Imprimatur Database
The Missing Imprimatur Group part of the Mulready group at
A Friendly trustworthy dealer in fine Line Engraved material

This site is a free site, but I would appreciate donations to help cover the costs!