some of my tomatoes are ripening quite unevenly, with the sun-exposed part not looking very red. Any chance this is some form of the berry "sun scalding" you all addressed in a recent question in the Baltimore Sun? Or is it something else?
Yes, it is similar sun scalding on tomatoes.
Here is our Tomato page. You can read about it and other common problems listed on the link under "problems" towards the bottom of the page.