Katherine asked me to show how I frame work, so .... here goes :)
This is how I framed the big mixed media and pastel abstracted flower.
The frame is over 3ft square and the mount was either 4 or 5 inches wide - I think it might have been 5 with 5.5 inches at the bottom. It could even have had a wider mount (mat) - but the framing costs got a bit much! My framer taught me when I was starting out that it pays to have an extra half inch at the bottom to stop the 'falling out of the frame' look that you can get if the mount is equal all the way round.
I don't use coloured mounts, just antique white - a soft creamy colour. I usually frame in limed ash - again a pale neutral colour that lets the painting be the key element. By using one type of wood they all look right together in a show. The widths of the frame may vary but the 'look' is the same.
I never frame work on canvas. I use gallery wrap canvas and paint the edges - usually in a colour that works with the painting and occasionally taking the painting around the sides.
This is a shot of part of a solo show I had - you can see that the frames work well together and there's a unity. Compare it with the jumble of frames from different artists at the LSA show, which really doesn't work too well!
On the far wall they are all in limed ash frames, some wide, some narrow - they look a bit washed out in this photo but in real life the frames work honestly! nearest to the camera you can see some small canvasses - I painted the edges in deep blue to echo the main colour of the painting.
The framed works were done plein air, the canvasses are studio paintings from memory.
In my experience, bad framing can ruin a good painting and good framing can make a reasonably good painting look great.
I painted on board (in oils) sometimes, in the first year when I was at uni, but don't nowadays because I find them so difficult to frame in a way I like. I don't like the board simply put in a frame as it feels cramped and claustrophobic to me (I know you probably think I'm weird but I really really don't like it!) - they look better floated but then it gets complicated. It's so much easier to work on canvas and forget the framing altogether!