The standard pen for writing is the HB, a hard line and dark pigment balanced. This system was developed in the early twentieth century and indicates the hardness of the pencil with a scale from BBB, the softer, until HHH, the hardest. The more letters you have, most are hard or soft. BBB is less soft mark with BB, then B will follow, and then it would come the hard starting and an H increased up to three.
If we make artistic picture, we will be more useful soft pencils, expensive shades and allow more mobility on the line. However, if we want to do technical drawing, a pencil lead us to confer greater precision in the stroke.
Today there are more types of pencils and the scale has been extended so that it can classify all grades. Also, instead of repeating the lyrics, we now show that the new numbers, the maximum, to bird, the least. The one, however, ignored the letter and put it directly. Thus we have a scale that ranges from 9H, the hardest, to a H, an F, an HB, the standard, the B and 9B, which would be the softest. The pencil F is slightly harder than HB. This is the picture of the pencil hardness:
| 9H | 8H | 7H | 6H | 5H | 4H | 3H | 2H | H | F | HB | B | 2B | 3B | 4B | 5B | 6B | 7B | 8B | 9B |
| Hard | → | Balanced | → | Soft | |||||||||||||||
| Category: | Another components | ||
|---|---|---|---|
| Materials: | Wood | ||
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