When painting the canvas, it is important that the entire intersection be painted, but that the holes in the canvas not be filled in with paint. A small pointed brush is needed.
For the small point canvasses, even a fine brush can fill in the holes if wielded at an angle. Since I frequently use 18 or even 22 point canvas, I find that an angled spotter works the best. This 5/0 angled spotter is my favourite for 18 point canvas like I am using in this Valley of Shadow design.