Hi Purrus,
We lived in a little duplex when we first got married that had coved ceilings. So pretty. Our had a little raised area on the wall where the cove started so it was easy to tell where the ceiling began. If it didn't have I would have taped off a level line just a hair below where the curve of the cove began on the wall and leave the ceiling white or paint it a light shade of the wall color.

Paint the ceiling as well. Contrary to popular belief, white ceilings don't always make a room seem larger. Having the same color wrap all around the room keeps your eye from stopping at the ceiling, which can actually make the room seem more spacious.

We just went through this exact thing and opted to paint the ceiling too. I have absolutely NO REGRETS and think it would have looked ridiculous to leave it white.

I just saw this on some show. What they did was what justgotobeme said - taped it off around 8' (the room was 9' or 10' high, I think, and painted the cove ceiling part white, and below the line a color. If you want, you could put a small moulding (1/2 round or somthing) at the line. I think this would look better than just the paint stopping, even though I've seen that technique a lot in Victorian homes. They talked about having coved ceilings and said the other option was what terriks said and to paint the entire thing. So, I guess you just need to decide which looks best in your home. Good luck! :)

I swear I thought I added why it would have been ridiculous. Whoops.

We live in a Houston suburb. Home of the cookie-cutter houses that are thrown up in mere months. That equals some pretty shoddy drywalling at times and corner joints at the ceiling are particularly painful. They would have been way too obvious with a break in the paint color.

I somehow missed that you were painting it a buttery yellow. I would definitely paint it all one color. Why oh why did they try to do cove ceiling if they didnt' know how to do them? YIKES! Got pictures? I'm really curious to see them now.

We have coved ceilings in our 1950 home. We opted for a shade called Vanilla Latte that is a creamy white, but not yellow. It looks clean and warm, but not dirty like some eggshell tints. We painted the ceiling and walls the same color then painted the hallway and linen closet visible from the doorway the same color to draw the eye through the small livingroom. It worked really well and I'm glad we didn't opt for a different ceiling color.