I've engraved drums before...and they are a real nerve-racking experience.
Almost all of the cuts are wriggle cuts and, in many cases, the engraving is done after the drum has had a final finish applied.
The color contrast is the actual brass (or whatever metal) shell that has been cut into.
....one slip and you're done.
But here's the plus: If you can nail down the technique, you can name your price. Trust me----there is a real market for this work.