This glaze is made of clay that our friend brought from the volcanic island of Madeira. The surface is brownish with spotts and when applied in thin layer it comes out darker, it’s matt and it doesn’t flow at firing temperature of 1250 ºC.
On this bowl (top to bottom): iron glaze, chalk glaze and Madeira slip
Slip made of Madeira clay
Madeira slip, the back mug is darker because the slip is applied in thin layer