As the book of " The sorrow of young Werther " was published in 1700's, I am going to forward for the concept which have pencil sketching styles and which familiar to old Victorian book illustrations.It is more about the comparison of the light and the expressive strokes. I am thinking to create a mono- environment to create the mood of the book and a same style but coloured character of Werther. These are the images which inspired and where I took the references from.
And the following texts is the part which describe Wrether in his out look.
"...Werther goes through life in his blue frock coat and yellow waistcoat..."
This gives me an idea of how he would look like and I have also look at the costume of the musical of the story which gives me a strong impression of it. However, instead of the clothing he is wearing, his body languages will bring him towards a character because of the sad story.