A painting knife is an artist's tool with a flexible steel blade used to apply paint to the canvas.
It has a pointed tip, lowered or "cranked" like a trowel, suited for painting on canvas. The blade can be of different lengths and shapes : triangular, rectangular or more diamond like.
A painting knife is different from a palette knife which has a straight wide blade and a rounded tip, better suited for mixing paints on the palette.
Famous knife painters are: Titian, Bob Ross, Frans Hals, Rembrandt, Fragonard, Courbet, Nicolas de Staël, and Riopelle.