The outside of the bowl had been polished but the inside was untouched, just cleaned by soaking in pickle. It is difficult to polish the inside on a polishing wheel and I also liked the idea of there being a contrast between the inside and outside.
I decided to take the idea of contrasting surfaces further and came up with the idea of creating the verdigris effect.
Verdigris is a green or bluish-green pigment. Its name comes from the Old French vert de Grece, which literally means “green of Greece.” It was used as the primary green pigment up until around the 18th century. Verdigris is a poisonous chemical compound. I created this effect by brushing the inside of the bowl with Copper Nitrate and passing the torch across it. The depth of colour is built up in layers.
In order to keep the effect it needs to have a coat of varnish over it.
Addition to post.
I also want to look at other materials to mix with this bowl.
I have made a ceramic dish (with impressed rice to give texture) which sits inside the bowl.
I expanded this idea and came up with making a ceramic dish with a 3D spiral.