New Pencils

I recently purchased a package of new pencils with a range of 'leads' and am learning about them and pencil history.  

Pencil 'leads' come in a range.  They are typically categorized as H (hard), B (soft; darkness), F (sharpens to fine point) or HB (hard and black).  For the H and B pencils, there can be a number, added to the letter, that distinguishes the hardness of that 'lead'.  H (hard) leads make lighter lines while B (soft) leads make darker ones.  In addition, the higher the number for the H lead, the harder the lead and the lighter the line.  For the B lead, the higher the number, the softer the lead and darker the line. 

In terms of the history of graphite used in the core of pencils, here are some key points:

• A major graphite deposit was discovered in England in 1565
• Graphite is a crystalline form of carbon
• Pencil graphite has no lead 
• Pencil cores are made of purified graphite power + kaolin (a clay binder)
• Hard pencils have about 20% graphite; soft ones have up to 90% graphite

As part of adding these pencils to my smorgasbord of tools, I did a line and shading test.  My favorites were the 4B and 7B, because of how they glided across the surface of the paper and the marks they made.  That said, I can see that the range of pencils, though, will be able to serve different needs.