Etching silver with the least amount of undercutting?

I’d like to try etching silver. I’d like to be able to create some
deep marks - possibly even going all the way through to the back,
with the most vertical sidewalls possible. I believe that the correct
way to express this is that I am looking for an “anisotropic” etch
that does not “undercut” the masking layer.

Which is better in this regard: electro-etching or chemical-based
etching?

And is there any difference between Argentium and conventional
sterling silver when it comes to etching?

HI,

I am not an etching expert, but I have etched Argentium Sterling,
using Ferric Nitrate. I added citric acid, to make it last longer,
as with Edinburgh Etch. It worked well, but I have not done it with
traditional SS, so I cannot compare. I have read posts from people
saying what to use as the liquid for electroetching SS, so I think
it is possible----check the archives. For etching all the way
through, you might look into spray etching, or having your work
etched commercially.

Cynthia Eid