These are three of the common types of pencils that are used by artists for drawing. You will likely already be familiar with graphite pencils having used them at school, they are also the most common type of pencil available and it does not take much looking to find them. The other two are more specialised and you will likely have to go to an art store to locate them.
Graphite pencils are made from a combination of graphite and clay while charcoal pencils are as you may guess made out of charcoal. Carbon pencils are made from a mixture of what is called lamp black and clay, although they may also contain graphite or charcoal as well. As different brands use a different mixture this can make different brands of carbon pencils vastly different from each other, unlike graphite or charcoal pencils.
Graphite and carbon pencils use the same system to determine their hardness which uses either “H” or “B” together or with a number, often from 9H to 9B. Charcoal pencils have a different system and are labelled soft, medium or hard.
Each type of pencil has a scale of values that can be produced with it, graphite for example tends to lean more towards the lighter values producing greys. While it is possible to get darker values you will not be able to produce the dark values that are possible with something like charcoal pencils. While graphite pencils lean towards the lighter values charcoal pencils lean towards darker values. Carbon pencils however are somewhere in between and as stated above the mixture of carbon pencils can vary depending on the brand this can change the value range that the pencil is capable of reaching as some may be closer to charcoal and some may be closer to graphite.
Each pencil has its advantages and disadvantages depending on what you plan on doing with it. Something that you may have noticed when using graphite is the shine that can develop when you attempt to reach the darker values. This is something that some artists don’t like and is one of the reasons they may use charcoal which does not produce this shine, although graphite does make adding fine details to a drawing easier. Depending on the brand carbon pencils can suffer from this problem as well, depending on the mixture that was used, but to a much lesser extent than graphite pencils. Charcoal pencil however have their own down sides which is that charcoal pencils can be messier than graphite and can be easily smudged, although this does make blending charcoal easier than graphite. Again some carbon pencils are also like this although to a lesser extent depending on the brand.
The quality’s of carbon pencils seem to lay on a scale between that of graphite and charcoal pencils. The carbon pencils that can produce the darker values are more like charcoal pencils than graphite and have similar quality’s, such as being messier and easier to blend but not to the extent that charcoal is. The carbon pencils that produce the lighter values tend to produce a shine but not to the extent that graphite does. This means that some experimentation will be required to find the ones that best suit what you are looking for.
While each type of pencil is a little different there is nothing stopping you from combining them to create a single drawing. This will also enable you to have access to a wider range of values while avoiding some of the disadvantages that some of the pencils have, such as the shine produced by graphite pencils. This will however require some experimentation to find what works and what does not.