When drawing in colored pencil there are a few things you need to take into consideration with the materials you use. Less expensive pencils are usually poor in quality as the pigment is suspended in a more waxy medium, leaving behind a shine and making it far more difficult to overlay the different colors that help blend areas. Pencils also come in different densities (hardness) which also allow you to make variations in line thickness, details and filling in area of color. The other matter you must take into account is the type of drawing surface you use, not only for color and tooth, but how sturdy it is. Unlike graphite, it is actually much more difficult to erase or lift mark when they are applied, so errors need to be covered up in a sense. The end result is a much more illustrative look than other media. It is time consuming but worth the effort.
Using charcoal allows the artist to get a drawing to a refined state in a relatively short period of time. To be sure it can become a messy process, but it is remarkably fast. On the other hand drawing in graphite requires a little bit of patience. It is a universal assumption that all artists are accustomed to drawing with a pencil from youth, but that does not mean we know how to handle it properly. As with all media, the better quality materials the better the results. Graphite pencils range in density (hardness) and darkness (tone). The hardness scale goes from 9H (hardest) to H, and the tone from B to 9B (darkest), the middle pencil is always an HB. The famous scholastic "Number 2" pencil is the equivalent of a 2B. Hard pencils give very sharp and precise lines and are best suited for architectural and engineering drawings. Tonal pencils allow a full range of dark values to be drawn without burnishing the paper by pushing too hard on the surface. To be sure drawing with graphite requires constant sharpening and a consistent stroke and pressure on the fibre of the sheet as well as holding the pencil vertically like charcoal and drawing with the arm instead of with the wrist. The above study of Rene is 20" x 30" and took approximately 12 hours to complete. A similar sized drawing in charcoal would have taken about 6 hours.