There are at least 20 different pencil lead options to choose from. Most but not all pencil manufacturers adhere to this scale.
As with any industry, there are folks with specific needs. Artists tend to favor softer pencils, and architects or engineers lean towards the harder ones.
Sadly, pencil hardness numbers from one manufacturer do not directly correspond to those from another supplier.
Pencil leads are typically a mix of graphite and clay, but some pencils contain carbon, charcoal, wax, grease or other materials.
In addition to the choice of hardness, we have lots of other pencil variables to consider - color, length, shape, size, etc.
TYPES OF PENCILS
There are wood pencils, plastic pencils, mechanical pencils and so on. And, I discovered, a number of people who are very excited about pencils. Here's a site I liked a lot.
If you use a mechanical pencil, then you have to know what diameter your pencil uses, or the leads won't fit. Here are a few common sizes (all measured in millimeters; I wonder why? German?):
0.5 (writing size)
THINGS YOU CAN DO WITH PENCILS (BESIDE WRITE)
1. Chew on them
2. Give your ear something useful to do
3. Test the hardness of a coat of paint or varnish. You simply make a mark on the finish with successively harder pencils, until you find one that scratches the finish rather than marks on it. TEST
4. Hold your clothes on the line. Here's a peg pencil, from designer Yuta Watanabe.
5. Prop up your iPhone on a pencil stand and watch the President give a speech.
6. Carry your annual calendar around on it. This is actually patented!
GETTING RID OF A PENCIL MARK
Erasers are made of rubber, vinyl, plastic, gum, etc. They work because the eraser is stickier than the paper, and the graphite would rather jump onto the eraser than stay on the paper. In the process, some of the eraser wears off, and leaves little flakes or pieces.
Some erasers are so abrasive that they wear out the paper - you have to be careful or you will have a hole rather than a clean spot!
The most popular erasers in the US have often been pink in color, but I started using this kind in a technical publishing job, and since then have favored it over the pink ones.
Here's a font called Eraser Dust. If you like the pencil look, you can download it for free.
No, we are not going to use this font on our Lesson Sheets ... you wouldn't be able to tell the kids' writing from our printing.
I like these stealth pencils shown on the PencilTalk blog!