Other than simply ornate, is there a particular name for these kinds of intricate, complex ceiling designs? Spoiler: Ceiling 1 Spoiler: Ceiling 2 Spoiler: Ceiling 3
Frescoes? Embossed copper or tin panels? Gilded wood molding? In the first picture, I think the carved foliage might be acanthus and the round parts are rosettes.
don't know about those particular ceilings, but if you're looking for general ceiling imagery, I'd go with vault or vaulted where appropriate... it implies space and security, like the ceilings somehow turns the room into a vault... gilded is always a good word because it implies opulence and the zeitgeist of the time, as in the Gilded Age, but I've found that the noun gild is a great off-beat word to drop in somewhere, mainly because nobody uses it... it's kind of like a sucker punch word, and there's always the alliterative possibility of adding gold into the phrase somewhere... curlicue is an outstanding world for describing all those ornate handcrafted features, in ceilings or anywhere else for that money... it's the kind of word that's fun to say and fun to write... you can build a sentence around curlicue, it's one of those fulcrum words that will dominate almost any passage it invades...
There are a ton of embellishments, appliques, onlays, motifs, shields, forms, and many other accents. The third is a kind of lacunar ceiling. A coffered ceiling with gold trim accents, and centered with an ornament in each of the lacunae or caissons (the flat panels in the sunken sections). The second is approximately the same, but installed in a curved ceiling. And the first looks like a finely detailed tin ceiling with murals and bronzed embellishments. This site can give you a lot of specific examples: http://www.decoratorssupply.com/store/main.aspx
Thanks to all for help on this. Lacunar ceiling is the closest I've found for a name-name for this kind of ceiling, so thanks @Dnaiel. The scene in question is pretty quick as it's just a walk through from one wing of the house, through the main hall, and then over to the other wing. It can almost be done without (the scene), but I'm using it to describe a moment of unhappy anticipation of what awaits one of the MC's over in the other wing. Descriptive words for such a ceiling, I have aplenty! My trouble is that I am wont to wax rhapsodic (economy is my goal this year), and while I wanted to give some description, it's not a moment for Architectural Digest, so to speak.