Academic school of drawing and painting involves working on formats not less than A3. But I don't always have the opportunity to paint on such a big paper at home. We have to use what we have, sometimes very small pieces of paper. Then to my rescue comes in a slim mechanical pencil whose thickness of the line is very thin and of constant thickness.
Here's a portrait I painted in stages, using my favorite mesh shading. On images well seen as I started, as continued to paint and how to finish.
I will be glad to any comments!