Kinds of darkness pencil

You must have seen the sign in pencil, such as 2B, HB, 5B and others.
for you who do not know, graphite pencils were made in various grade. Pencil has a different graphite content, so does the level of hardness (hardness) pencil core. The rank of hardness, grade pencil roughly like this:

(louder) .. 4H - 3H - 2H - H - HB - B - 2B - 3B - 4B - 5B ... (more lenient)

The more soft pencil, the resulting value will be even darker.
 This is an example of the color chart on the thickness of a pencil
 

 Chart on the left I made with various grade pencil. As you can see, I use the pencil of 3H to 8B. Box with the code "0" means that I do not love shading, so the color white was the original color of the paper.
How to get value variation with only one type of pencil? That is by playing a pencil on the paper surface pressure.

To get the light effects such as 3H pencil, use a 2B pencil is thin and not too pressed. Instead, press firmly 2B pencil for shading the dark, dark pencil 3B, 4B, and so on.

This second technique can you do if your pencil limited ammunition.