The middle slot is simple 45 deg mitre . A wedge under the work will give a cut for a compound mitre .
45 deg mitre and slope for canvas stretcher .
Genuine Indigo Oil emulsion on paper
Painting studio wall green like the landscape rooms in the Musee d'Orsay and the National Gallery-work to do on these two Wiltshire canvases. BBC4 last night Archeology of the area from the air .