Pencils
A quick word on pencils
HB
9B
9H
H = Hard and B = Black They range from 9H to 9B with HB sitting in the middle.
An HB is fine for design work. High Bs (e.g. 5-9) can get smudgy and make a mess of your hands and page and the high Hs are too hard.
Harder pencils are more difficult to rub out as they indent the paper more and when you rub with your eraser the rubber goes over the indent and doesn't remove the graphite.