Most of my paintings on stretched – mounted canvas have painted edges like shown in the picture below. Therefore you don’t need special framing. All the painting have varnish layers to protect from dust as well as ultra violet rays to prevent fading of colors.
Gallery wrapped canvas with 1.5” depth and the standard stretched canvas with 0.5” depth both look elegant with a floater frame like in the picture below.
Art on paper needs a frame either with or without a mat and should have a glass or acrylic frame in order to be protected.
Art on unstretched canvas could be framed exactly like art on paper, however it doesn’t need a glass or acrylic frame.