The type of engraving you are describing is called "bulino"
engraving. It consists of hundreds of thousands of tiny dots and
lines. Similar to banknote engraving, but you will see more lines in
the banknote style. Pull a bill out of your pocket and look at it
under magnification to get an idea...
The absolute best of this bulino style work is illustrated in the
book "Creative Art" by Marco Ettore Nobili. In Italian and English,
and kinda pricey at $100, but worth every penny to aficionados and
serious collectors of the finest in hand engraving. There is no ISBN
number on my copy.
If you visit the fega.com site and look under the educational videos
- you will find one done on bulino by Chris DeCamillis at the 2004
exhibition. I believe it is priced at $33.00 and to my knowledge is
the only video on the technique currently available. It should give
you a good start...
Let me know if you need further
Brian P. Marshall
Stockton Jewelry Arts School
Stockton, CA USA