This is a drawing of a Raven, using the medieval technique of 'Silverpoint on a Robin-Egg blue tinted Ground, on hand pressed paper.
While studying the techniques of the masters (Da Vinci, et al)., Silverpoint was one of the styles used verses ink and charcoal, that I wanted to learn.
Silverpoint is a very old type of Metalpoint drawing technique. Over time, the lines created from the silverpoint will tarnish, while the design of the bird remains the same.
More Info: (If you are curious)
https://en.wikipedia.org/wiki/Silverpoint