Turning Photos into Line Drawings

One of the steps I'm taking in creating The Dark Ones trailer is turning photos into line drawings. Ultimately, they'll be colored and shaded comic book style, but I have to start with the line drawings. I could do the "ink" manually, meaning on paper with actual ink, but I've opted to play around with some digital techniques.

I started with this tutorial: Turn Photos of People into Line Art by Melissa Evans. She has quite a nice portfolio of work, much of which involves portrait type things done digitally.

So far, I've created one background and two figures using the techniques outlined in her tutorial. Now on to coloring and layering.

Kneeling Outline

Standing Outline

Prison Cell Outline