After a bunch of improvment, back to this master piece (source BNF Gallica)

The challenge is to use a rollerball BIC with pressure variation to render grey level

– SRC file : 5000 x 2000 pixel

Render :

– 49 cm x 20 cm of drawing (on A2)
– BIC black pencil
– 17 hours
– 68000 lines, 163 meters done

Conclusion : Great …. grey level are good