Cardboard Paper Stock has cloth in the fibers, compressed. Thickness prevents bleed through and ripping of lines.
The fibers are from light eraser bumps, and the use of graphite versus my personal choice of lead pencil. Best move is woven cloth to pick up lead, which leaves a nice light line for ink. Lines left too heavy will bleed the black outline. Solution: Use plenty of white and a fine tip number 512. Or a Flame Throwing propane lighter torch. Or a Zippo.
Set fire to the Art. As if you were burning the hair from the arms of bears. Not a torch, but a real flame of love labor. X