OK! So your drawing subject is lightly sketched. You now want to add shading. But, how do you know where to add each of those light, medium, and dark values? A little tool called a value map is used by many accomplished artists to figure out the correct placement of values in drawings (or paintings)!

I found this lesson very interesting.............. and explained so well.
Many thanks

This is an interesting lesson. Useful info.

This lesson is great. I learned a lot. I think this lesson also helps to adjust the eye of an artist I really recommend this lesson for all the people who's got problems with lights and shadows.

Very usefull lesson!