I'm considering a couple things to get this done. The first one is simply painting the engraving on the sword with a lighter color (I'm thinking gray) then paint black carefully around it to clean the sword back up. Another option I've considered is simply painting the sword in a gray, then giving it a black wash a couple times. Depending on how thickly I apply the wash, this will give the sword natural definition, shading, and highlights...but it will be difficult to pull off I think. Not only that, I'm not sure if it'd look right with the rest of the model.
Thus, I welcome any advice or alternate methods to painting this. As I said, I want to keep the sword black but I want to be able to read the script engraved on the sword if possible. Any assistance would be most appreciated. :)