In many of my classes I teach the importance of understanding and using lines in sketching. From bold lines to thin lines, crosshatching to stippling to repetition- using a variety of lines will bring a sketch (or even a doodle) to life! A great way to practice and challenge yourself to work on lines is by using the concept of subtraction. This means that instead of adding pigment to a surface, you are pulling it away. There are all kinds of ways to do this but one of my favorites is using scratchboard. It is affordable, easy to use and a wonderful way to exercise your brain when working on your drawing skills!
All you need to scratchboard and a scratching knife- I purchased mine HERE
And then you scratch,
and scratch some more!