Black is the absence of colour or is it ? It is the complete absorption of light
A black writing pencil has Graphite and is really a deep grey . Graphite is a different form of natural carbon like a diamond but is soft . It has a metalllic sheen and powdered is mixed with different porportions of clay and surrounded by wood to form pencils . The different quantities of clay decide the hardness or softness of the pencil. Softer the pencil, darker are the lines . Unfortunately the lines can never be really really dark like black because of the shine which gets worse the more it is layered . Also graphite lines cannot be covered by either oil paints or charcoal, the metallic quality shuns these .
To make blacks really black, we need carbon as carbon, in its original form. The powdery is also combined with clay to form pencils of varying softness. A carbon pencil can be sharpened to a point and is excellent for really dark blacks without a shine . Detailed work can be done as it can be sharpened .
Charcoal , the basic burnt wood, or ivory or bones has coarser particles which disperse light and so is less black than the carbon pencil ,but both can be easily blended, brushed off and can be covered with graphite and oil paint They so are good for doing the under drawing for a painting on canvas . Charcoal is great for drawing textures especially in larger areas.
So much to learn ……even about the absence of colour !!!!