Todd Klein, comic book letterer supreme, has a fascinating article up on his blog about the process and thinking behind his letters for Alan Moore’s Tom Strong. One of the images is a snippet from his style sheet for the different lettering styles used for each character, about which he states:
This is not something I usually have time to do. On books like SANDMAN, the many styles were added gradually, as the story called for them. And I should add that I’m not a fan of using a variety of lettering styles for no good reason. They should be there only if they add something to the story. In this case, I read the script for the first issue, and I saw all these iconic pulp characters that seemed to call for individual styles.
He also goes into detail about the thinking and influences that went into each character’s word-bubble style.