The picture is from a photograph from a National Geographic article in 1980 about a man who refused to move from his house near Mt. St. Helens right before it erupted.
Next, I did a bunch of experiments with colored pastels, both chalk and oil, but I found these frustrating. Chalk is so dusty I'm always afraid my drawing will blow away or disintegrate, oil is more substantial, but harder to precisely mix. I did find some water soluble oil pastels that mixed more easily, but haven't done anything with them yet that I really like.
Then I decided to get back to basics: markers! Well, 'brush pens'- that's what they call them when they are marketed to adults. But still, they are basically markers. Markers are fun. Markers are bold, fast to work with, hard to mess up after the fact, and you can still do some simple mixing with layers.
This picture is based on a postcard Jane sent me. Jane has excellent taste in postcards.