Here is Alan Lee again, and what a marvellous comment it is:
“My preference is for working in analogue – charcoal, pencils and watercolour; I like the organic and tactile nature of pigments, burnt wood and water, and the sense of working within a tradition. I enjoy the extra possibilities and effects offered by Photoshop, but a sense of limitless possibilities combined with a loss of connection is ultimately a bit dissatisfying.”
Tolkien approves!
Here is the whole article:
And an example of his sketching: