Define the term sfumato. Name the above fresco and its artist. Explain how the artist how the artist used sfumato in his/her piece?

sfumato ( it's an Italian word sfumare ) is to tone down in printing or drawing the shading between colour and tone

technique of oil paintings which colour or tones are blended in such a subtle menner that melt and one another without perceptible transition,line or edges

shading the perduces soft and between colour and tone

what are the terms?