Someone who purchased one of my oil paintings on paper framed it so beautifully that I wanted to share her photo of the finished piece. She says it was framed by the Providence Picture Frame Company, a "firm that's been around since the 1800s, so they do a good job!"
I think my small paintings on heavyweight paper look best matted and under glass, and I love the way the edges of this painting are not covered by the cut mat. The substantial size of the mat looks great too, giving the small painting more impact.
As for my paintings on board, I always recommend this floating panel frame made by the Metropolitan Picture Framing Company. You can order the frame online, and simply specify the size of the painting and the "float size"- the size of the gap between the painting and the frame. I always use a float size of 1/8 inch.
For an alternative, here is my small (6"x12") painting "Lilies and Blue Table" framed by the buyer in quite a different way. I like it!
Lastly, here is an image of one of my drawings, framed beautifully and photographed by the purchaser, artist Don Gray: