I drew this study from a live model in charcoal and white chalk on brown wrapping paper. It was made in preparation for a National Geographic illustration.
I drew the study instead of taking a photo because it's faster. In 20 minutes I had all the essential information I needed. Getting a pre-digital photo printed out would have required driving to the one-hour-photo place at the mall or shooting a Polaroid (which I never used).
Here's a detail of the figure in the final painting, along with other figures that were also based on charcoal studies from models. The model for the guy working the lever on the ground is ski instructor Mike Rogan, back when he was still in high school.
|Iron smelting at ancient Populonia, from The Etruscans, National Geographic|
Tone paper studies are one of the oldest of old-school methods, and it's still one of my favorite ways to develop reference for multi-figure work, not only because it's efficient, but because it allows me to immediately begin selecting significant details and making a statement.
More old-school methods in my book: Imaginative Realism: How to Paint What Doesn't Exist