I don’t put frames on my paintings because I don’t know where they might be hung. Since I don’t think that a painting should match the room that it’s hung in; the frame acts as both a separator and a method of matching the painting to the room. I noticed a couple of frames the other day that were a little different, a simple black or dark brown frame combined with a relatively thick white inner frame. The picture was an average size (small for me), on a relatively deep rust yellow wall. This type of frame is likely quite common but I first noticed it with this photo.
I thought it looked great but I’m still not going to put any of my paintings in frame, but it’s nice to be able to give suggestions to a customer. The inner frame could be a colour that would match the painting or room but it’s a good idea to just leave it white so that it acts as a separator between the painting and the room, so then the painting could be hung in any room. The wide aspect of the frame offers more separation and should be more suitable to different room decor.