Graphite Grading Scale
Pencil leads are made with a mixture of clay and graphite, they can be made harder with the addition of specific waxes or resins and softer through the addition of clay or by the exclusion of wax. Different ratios create different results. There exist two systems when it comes to grading pencils, European and American.
The most common one is the European, which uses both numbers and the letters H and B.
H stands for hardness and B for blackness.
The higher the number next to the 'H', the harder the pencil lead inside is. The higher the number next to the 'B', the softer the pencil lead is, making it leave more graphite on the page.
Hard leads give clean and light lines, they are useful for outlines, small details, technical drawings, light sketches, etc... When sharpened they tend to be quite sharp and difficult to erase.
Soft graphite is darker in colour since the lead deposits more graphite material on the paper. It is perfect for drawing and shading as artists can take advantage of the brush-like expressions. They could smudge easily and consume faster, but be smoothly erased. They require more sharpening since the soft lead will lose its point quicker.
- B grade pencils have a soft lead
- H grade pencils have a hard lead
- HB falls in the middle, they keep a great balance and are used for both writing and sketching.