The ratings are based on my own personal opinions, formed by thirty-plus years of collecting comics by specific artists. Each cover and story is rated in relation to that artist's overall body of work, not by comparison to other artists. For example, a three-star Frazetta cover is not necessarily equal to a three star Ditko cover, but a three-star Frazetta is better than a one- or two-star Frazetta. Ratings may change based on newly discovered works. I try to apply art history and design principles when evaluating, but it's still just one man's opinion. Feel free to agree or disagree in the comments section.
***** = Brilliant: a perfect or near-perfect effort by the artist
**** = Excellent: a superb effort with minimal flaws
*** = Good: a solid but typical effort by the artist
** = Mediocre: an effort by the artist that falls below expectations
* = Poor: an nearly unrecognizable effort by the artist