Why Paint With a Blade Instead of a Brush? Thickness You Can See

The blade is thin steel, flexible along its length, usually cranked so the handle sits above the working surface and the hand clears the canvas. Used for its original purpose it mixes colour on the palette and scrapes it clean, which a brush does badly. Used on the painting itself it lays down paint in a completely different way, pushing a quantity across the surface rather than dragging bristles through it, so the paint arrives in a slab with a clean edge where the blade lifted. Thick paint keeps the shape it is given, holding ridges, peaks and the marks of the blade, so the surface becomes physically three dimensional and catches light from whatever direction it falls.

A small number of actions produce most of the effects:

• •Loading and dragging, which lays a flat slab with a sharp trailing edge
• •Pressing and lifting, which pulls the paint into peaks
• •Scraping back, which removes paint and reveals what is underneath
• •Edge drawing, using the side of the blade for a fine line
• •Mixing directly on the canvas, so two colours meet without blending fully
• •Flattening an area, which pushes paint into the weave and kills texture deliberately

Paint applied thickly changes how a picture reads, and the reasons are physical rather than stylistic. Ridges cast their own shadows, so the surface changes as the viewer moves and as the light in the room shifts, which a flat painting does not. The marks record the speed and pressure of the hand directly, so the making of the picture remains visible in the finished object. Colours placed side by side without being mixed stay separate and mix in the eye at a distance, giving a vibrancy that pre-mixed colour loses. And the thickness itself reads as material, which is why paintings made this way look substantial in a photograph and considerably more so in a room.

Thickly applied paint has a history that runs from an occasional flourish to a whole approach. Rembrandt built highlights in jewellery, armour and flesh from paint thick enough to stand proud of the surface, which catches real light and makes those passages glitter in a way no flat painting achieves. Turner worked increasingly with knives and fingers in his later years. The impressionists and those after them applied paint in loaded strokes that stayed visible as strokes. Courbet used a blade extensively for landscape and rock. In the twentieth century the technique became central to several painters who worked almost exclusively that way, building surfaces centimetres deep, and conservation of those works is now a specialised problem of its own.

Working this way imposes real constraints that account for why it is used selectively. Thick oil paint takes far longer to dry, with a heavily loaded passage remaining soft for months and never drying evenly through, which causes the surface to wrinkle and eventually to crack as the outer skin sets over a soft interior. It consumes paint at a rate that is significant with expensive pigments. Detail is difficult, since the blade is blunt compared with a brush and small marks are hard to place. Corrections mean scraping off and starting again rather than painting over. And a thickly built surface is fragile in transport, since a raised ridge is exactly what a careless hand catches.

A flexible blade pushes paint across the surface in slabs rather than dragging bristles through it, and thick paint keeps whatever shape it is given. Dragging, pressing, scraping and edge drawing produce most of the effects. Ridges cast their own shadows so the picture changes with the light, and unmixed colours stay separate. The cost is slow uneven drying, heavy paint use and a fragile surface.