This is an example of:
20mm x 30mm walnut with a walnut wax.
With a 5mm lift using foam board to create the shadow effect.
Then 30mm white mount around the float.
And spacers the same colour as the mount board that separates the mountboard and the glass. This gives the frame a box effect.
And with Anti-reflective glass (Artglass) this protects pictures from UV rays as well as giving it the highest possible clarity.