
1) Painting technique
Found on
https://www.crosswordclues.com/clue/intonaco

Intonaco is an Italian term for the final, very thin layer of plaster on which a fresco is painted. The plaster is painted while still wet, in order to allow the pigment to penetrate into the intonaco itself. An earlier layer, called arriccio, is laid slightly coarsely to provide a key for the intonaco, and must be allowed to dry, usually for some...
Found on
http://en.wikipedia.org/wiki/Intonaco

(from the article `fresco painting`) ...made a full-scale cartoon (preparatory drawing) of the image that he intends to paint, transfers the outlines of the design onto the wall from a ...
Found on
http://www.britannica.com/eb/a-z/i/34

(formerly in fresco painting) the last and finest coat of plaster, usually applied in sections and painted while still damp with colors ground in water or a lime-water mixture. Cf. arriccio.
Found on
https://www.infoplease.com/dictionary/intonaco
No exact match found.