Knapping studied under E Aubrey Hunt in England, and in France and Belgium, and is listed in Benezit as being from Blackheath. Her first exhibition in Cornwall was with the RCPS in 1897, the picture having a St Ives title. In 1905 she took over William Holt Yates TITCOMB's Piazza studio when he left St Ives, purchasing the freehold of the entire block in 1920.

She was an exhibitor in the 1911 Show Day in St Ives, and later in the Show Day of 1924 when she showed several oils, one still life of tulips, a maritime scene entitled St Ives Harbour, and another termed 'a nocturne' - all 'decoratively treated' (St Ives Times). 

A member of the Women's International Arts Club, she also designed Christmas cards and illustrated children's magazines. A keen golfer, she divided her time between St Ives and her house in Sloane Street, London. A much respected artist, on her death she bequeathed the Piazza studios to the RBA, in the hope it would remain artist studios.