Once I had my preliminary concept drawing, I gathered my reference shots and did
a detailed drawing on a 11x14" sheet of Strathmore Bristol Vellum paper with a 2H
mechanical pencil. Some parts were drawn freehand, others by using a light box (the
fresco in particular, since I wanted it to be as close to the real thing as possible).
When finished, the drawing was messy with a lot of stray lines, which was not good.
The next step was to clean it up and define it.
Using a dark umber pencil by Berol Verithin (these are basically Prismacolors with
hard leads), I went over the drawing to define the lines. Once finished, I carefully
erased the underlying pencil lines, using a kneaded eraser. The drawing was now ready
to be colored.