I have nothing I can add to the previous suggestions of bluing or blackening or paint to darken the cuts to show the engraving off better. These all work fine, so just try them out to find what works best for you.
If a person wants to preserve the bright cuts and their ability to bounce light, as David Rase suggests, do your line engraving, background stippling if needed, then darken the cuts ,and then come back and do your bright cutting last.
The engraving detail will show to advantage and give you that jewel like quality of the facets.
I've done this with Colt SAAs and it works well.
Mark