UD Etchings

Bought a box and would like to know how to tell the difference between some of
the different parallels.

For example I have three Etched in Time cards. The first has a copper colored
design with a black signature and is numbered in copper. The second is also
copper colored design with a blue signature and is numbered in silver. The
third is in a silver design, signed in blue and numbered in silver.

Any help with this edition would be helpful.
Thanks