Article creator

That is the user who created the article. The article creator is set automatically. In a copy-driven workflow, typically, it is the same person who writes the article, thus creator equals to author. But in a layout-driven workflow, the article creators are typically page designers, as they create articles and assign them to writers.

Article author

That is the user who writes the article.

This attribute is often used also for a personal assignment.

The article author is set manually.