The 1st painting is called japanese bamboo painting. The 2nd is called Degas Portraits à La Bourse. They are both one brush single stroked paintings. But the 1st is ink and the 2nd is oil.... SOOOO I hope this gives you and understanding.....
Picture 1: This drawing is an example of vine charcoal. The medium used to create vine charcoal drawings is made by burning plant material, such as bamboo, into different consistencies. Picture 2: This is a chalk drawing. Chalk is a soft calcium based drawing medium made from ground minerals and fossilized shells that are mixed with a gum or resin.