It was different from other canvases, because it was passed between two cylinders of a machine designed to flatten the warp and weft threads. This was done in order to make it easier to draw a design upon the canvas.
GVE
Flattened French canvas, or French canvas, is a nineteenth century form of canvas widely used in France. It was made in cotton, flax or hemp, and sometimes cotton with flax.
It was different from other canvases, because it was passed between two cylinders of a machine designed to flatten the warp and weft threads. This was done in order to make it easier to draw a design upon the canvas.
GVE