Esterbrook Pens ad
Esterbrook pens ad found in Collier's Magazine, December 24, 1954. I loved the individual characters for each of the pens shown. Looks a lot like JP Miller, but I'm pretty sure it's not. No illustrator credit given.
Here's a high-res version of it for you: Esterbrook Pens BIG. It was very difficult to get the right levels and tones here - the subtle grays in the illustrations were so fine and delicate, it was hard for me to find the right look without blowing the image out too much. Sorry.