A large deposit of pure graphite mineral was discovered in England in the sixteenth century by a group of soldiers. Artists and writers were attracted to this graphite and they used this graphite on paper or vellum. This graphite drawing material is a solid material which is trimmed like a stick and placed in between wood in order to hold them well. This graphite lead creates dark marks or pints on paper.
By 1700s the availability of pure graphite material is diminished, but there were other locations where less pure graphite material was available. And this less pure graphite material was mixed with clay and formed into thin rods and baked in a kiln. Later on it became a popular method for preparing graphite drawing material. Graphite pencils used everywhere where there is a need to write or draw starting from schools to offices but depending on the grade of these pencils some are not very good for drawing while some are the best.
There are other types of pencils to use for drawing
Charcoal Pencils: Charcoal pencils generally produce darker lines because the particles are irregular and do not reflect light well. They are not as smooth as graphite
These pencils are best to use while shading skin tones, wood, fur, bark, eyelashes, shadows etc.
Carbon Pencils: Carbon pencils are mixture of charcoal and graphite which produces smooth and dark lines. It is difficult working with the carbon pencils in the beginning. Additionally, charcoal is not as easy but can still be erased but carbon pencils cannot be erased. Carbon pencil has both benefits of charcoal and graphite which provide different degrees of smoothness depending on the combination of graphite and carbon.
Graphite drawing pencils: Graphite pencils are used for drawing. They have different hardness scale marked on them which can be used to make the drawing light to dark. Here is a rough estimate on the markings of hardness and softness,
4H - 9H is very hard
H - 3H is medium hard
B - 4B is soft
4B - 9B is very soft
Few tips to get the best out of your graphite pencils
Always keep your pencil sharp in order to achieve a good drawing.
Drawing lines using pencil has different weights. You can vary the weights of the pencil by lifting the pencil away from the paper or pressing it harder. The lines may be dark or lighter due to these effects.
To shade the area of paper evenly move the pencil back and forth movement over the same area, changes the pencil point direction and the whole paper can be shaded evenly.
Avoid the shading in curve form that is according to your arm. The direction is controlled along your object. To achieve this create an edge using contrasting direction in two planes.