Design and style
A frame needs to suit your style, your home and the painting itself.
Paintings on board can be framed in two styles. Either in a traditional frame, where the painting is loaded from the back and the frame overlaps the edge of the painting. Or, in a floating frame where the painting is installed into the frame from the front and the gap between the painting and frame makes it look like it is floating.
Oil paintings, traditionally, do not need matting (a piece of card added between the painting and the frame). Similarly, glass is not typically installed in framed oil paintings. This is to allow the painting to breathe as it continues to oxidise. If you do choose to add glass to your frame, make sure it doesn’t touch the painting to avoid damage.
Consider the material of the frame - do you want a contemporary, sleek look or a warm, traditional feel? To choose the colour of the frame, consider taking inspiration from colours in the painting or going for a neutral colour to let the painting stand out. Lighter colours immediately around the painting can give it visual space so it doesn’t seem cramped or swamped by the frame.
The size of the frame should be proportional to the size of the painting. Ideally, a traditional frame will be 1.6x the size of the painting.
I suggest using this website to generate free mock-ups and test out different frame styles.
Practical decisions
If you’ve got your heart set on hanging your painting in a hot, bright or humid place, your framing choices can help prevent damage. Special glass can be used to prevent UV light from fading your work. Similarly, your frame can be sealed to protect your painting from humidity or pollution.
Hanging
Ideally, use a double fixing on either end of the artwork (rather than a single central fixing). This will prevent it hanging forward, moving when someone brushes past it, or even falling.
Always err on the side of caution and use bigger fixings that you think are necessary! You may need to ask your framer to incorporate this into your frame.