Bronze Casting - Step 20
Sandblasted Bronze Cast

After the last bits of shell are removed, then you do any final surface work - called "chasing" in the jargon - you deem necessary. Some statues have a highly polished mirror finished (very difficult to do well), or as here, the final chasing was followed by sandblasting so we can add a patina.

Eventually a bronze statue - if nothing is done to the surface other than sandblasting or polishing - will form a natural patina. The color varies depending on the age and what's in the air. Green is common but some statues turn brown and even black. To hasten along the process nowadays it's usual to add a chemical patina by brushing certain chemicals on the surface often (but not always) preceeded by heating. Artificial patinas can be green, brown, or black, but also red, yellow, white, blue, and most other colors. For the really best patinas, the artists actually hires - yes that's hires a specialist - called a patineur - to do the job.