I think either will work, but you have to decide how you want it to look. Painting it the colour of the ceiling will emphasize it, and painting it the wall colour will make it blend/disappear.

My personal choice would be the ceiling colour. If you don't like it it would be easier to paint it the wall colour later yourself than vice versa. I like the idea of highlighting it.

Thanks for the response -
I noticed that my thread was gone so I re-wrote it! Not sure how I can delete the extra thread.

I will have them leave it ceiling paint but they will be here all week so I can have them come back upstairs to paint it if I feel it needs it.

We have two arches in our house just like yours. We opted for painting the underside with the wall color.....as if the arch were "cut out of" the wall (it'd therefore be that color). BUT, like Budge1 said, you could try it in ceiling paint first since it would be easy to paint the wall color over it if you decided the other way.

Tracey

Here's the arch in my living room - I did both. I think I was low on paint.
Which looks better to you?

I like the wall color on the arches. We have several in our house too.

Lindy - I think I like the wall color! Daisy - thanks for posting that picture bc it helped me decide!

Just went up to check on their progress and see if I wanted the arch painted the wall color. Yep, it's going to be the wall color!! I can always paint it the ceiling color later but at least they have prepped the area! The parchment looks awesome!!
Thanks again for the quick response and pictures that really helped.