Each piece begins with a visual problem to solve, ideas, and a discussion about your goals for the project.
Concepts are roughed out and narrowed down, based on what is and isn't working to communicate the science.
Final sketches are prepared and approved for accuracy. Color studies will be completed, and a final color palette picked. Once this step is complete, production can begin on the final piece.
After the finalized sketches are approved, rendering of the final artwork begins. It might be line, tone, or color, depending on your storytelling needs and your budget.