painting an arch

In my apartment my living room and kitchen are separated by a rectangular arch where a door would normally be. I like the set up but have a strange compulsion to paint the arch, I don't know why.

The living room is an off-white and the kitchen is tiled but the same colour. My idea was to paint the arch a slate colour (i.e. dark grey).Not sure if it would work though. Any one any suggestions?

Its often a good idea to paint a signiture area in a colour that is elsewhere in the space, so in your case both areas are white and grey would be fine but if there was a strong colour scheme either in the flooring or dining suite / furniture it would be good to pick it up in that small area you are painting.

Excellent! That'll get me thinking, thanks for that!