I recently started using a ballpoint pen (everyday type-nothing special) to do life drawing. In the past I used (and still do) a Platinum Carbon Cartridge pen. But the advantage for me in using the ballpoint is that I can easily get more values with different pressures and almost mimic the look of pencil but with more boldness. These recent drawings were done on a rather “toothy” paper so it was easy to get a variety of light and dark tones with changing the pen pressure. I can get a softness that’s not available with the Carbon pen.