Do you know what the things you use to draw and paint are made of?

In this blog we will learn what the tools we love consist of. From the rubber to the paint, there will not be secrets for us anymore!

To start drawing you need a pencil, a paper and a rubber, but what is a pencil made of? It is made of carbon. But isn't the diamond also made of carbon? Of course, so why do a pencil and a diamond have such different properties? Because carbon has two very famous allotropic forms: 

• Cubic (= diamond, see image 1). Each carbon is connected to 4 other atoms of carbon (sp3 ibridization);
• Layers of graphene (= graphite, see image 1). Each carbon bonds 3 others (sp2 ibridization);

The cubic structure and the strong bonds between the atoms of carbon make the diamond the hardest mineral on the earth. 

On the other hand the forces between the layers of graphene are week and this makes the mineral flakable. When we write on a sheet, it is this property and the friction with the sheet that allows us to leave a mark on the paper.

By the way, a pencil isn't just made of graphite but also of clay and others minor components. In fact, the final pencil is made by a process of estrusion and sinterization of their powders mixed together to form a "pasta". 

Most importantly, the clay/graphite ratio determines the hardness of a pencil; as the ratio increase, the pencil became harder. Despite it, there is still not an absolute parameter to define the hardness of a pencil, nor a standard method to prove its hardness. 

As many people knows, we use a British classification system (in Europe), which uses letters and numbers. In particular:

• B (= black), indicates the softest pencils (the ones that make the darkest lines). Those pencils are numbered from 1 to 9 (from the softest to the hardest)
• H (= hard), indicates the hardest pancils (the ones that make the lightest ines). Those too are numbered from 1 to 9 (as the hardness increases).
• Between this two class of pencils, there are two intermediate "level of hardness" HB and F. 

There are other methods of classification, but they are all obtained in an empirical way, through graphic experiments made by the specialized technicians of each company without using a standardized method. The result is that the graphic lines obtained by two pencils (with the same hardness) from different company may be slightly different.