The 'Lilium' by Marco Mazzoni series has portraits that can awe you and scare you at the same time. Some pictures have eyeless face, which are replaced by flowers. Everything you see in the gallery is created with pencil coloring.
Marco Mazzoni did a good job of covering up the fact that these portraits were made with pencils because the pieces look like watercolor from afar. However, if you look closer at the 'Lilium' by Marco Mazzoni then you can see the pencil strokes.