Almost every piece from my shop has been heated to forging temperature and shaped on the anvil. Hammer blows give a texture to the metal that flat black paint obscures.
Unless specifically requested by a client, my interior work is finished with clear varathane and waxed or simply brushed with linseed oil and baked. These finishes show off the patina of hand wrought metal while repelling water.
If a piece is in a room where extremes of temperature are common, water vapor will condense on the cold metal in the warm-up phase of the cycle. Items exposed to rapid temperature shifts or extremes benefit from an annual wipe down with a bit of furniture polish (car wax or mink oil will also do the trick).
Most of my exterior sculptures are untreated. Rust is a natural colour that works well in a garden setting. Where rust is not desirable, other exterior finish options are available.