I had a blast painting it — even though I was working with a nasty cold at the time. It came out far better than I had hoped.
Below is the finished piece, by itself. It's 15" x 20" acrylic on illustration board. The pictures after it are minimized step-by-step of my process.
The basic idea of the painting was to give fans and readers a short rundown of what happened at the end of the last movie, but in the style of an old pup fiction novel or serialized movie poster. Props to my wife for the idea!
First, after I figured out the size, I did a very (VERY) rough comp of how I wanted to compose the images. I went through several sketches before I decided on this one. Then I scanned it in, colored it and added text in Photoshop.
Then I did several pencil sketches of Hogwarts, Harry, Ron, Hermione, etc., scanned those in and composed a tighter comp to use as a guide. I also used photos for certain elements like Draco, who was a last minute addition.
Then I printed out the comp and projected it onto a gessoed piece of illustration board. I lightly drew the basic features so I wouldn't get graphite smudged all over the gesso.
Then I proceeded to paint it using thinned acrylics.
And here's the how the final piece appeared in the Salt Lake Tribune's special Harry Potter section. The final layout was done in InDesign.