al aguafuerte

así como al humo, al óleo, etc.

The original sentence:

Las láminas de cobre grabadas al aguafuerte

and my attempt:

The copper laminae that were etched engraved
or
the copper laminae that were engraved to the etching
or
the copper laminae that were engraved by means of etching

The copper plates engraved with etchings...(verb)....

(It seems a little redundant since etching is a kind of engraving, I think.)

but in Spanish doesn't sound redundant, since aguafuerte doesn't exist as a verb.