A frame can do a painting as much good as harm. Before you spend money on framing, it is worth thinking for a moment – and sometimes it turns out that a frame is not needed at all.
For a modern painting, closer to abstraction, light frames suit better: white or silver. For a traditional and realistic one – darker ones, black or brown. The color of the frame itself should harmonize with the palette of the painting, so it is safest to choose a shade which already appears in it or is close to it.
Too wide a frame will dominate the painting, too narrow a one will not give it room to breathe. It is worth looking at the proportions and choosing a frame in proportion to the format of the canvas, not to the size of the wall.
Wood is the most popular and adds warmth and a natural character to paintings. Metal looks more modern and gives a more elegant, cooler effect.
On my site I place example visualizations of interiors and of the framing of my oil paintings. I can help you choose a frame by making such a visualization with a photograph of your interior or with the color of the wall on which you are planning to hang the painting. This helps very much in making the right choice.
I recommend to my clients that for some time they do not frame the painting, but simply hang it in the interior. Sometimes it turns out that it presents itself best without a frame. My paintings have their edges painted white and even without framing they look elegant.