Brass is the warm one. Under a filament bulb it goes properly golden, and it is the finish that stops a plain white wall looking like a rental — which is why it is the one most people picture when they think of a wall light at all.
Against natural oak it is a tonal match: two warm materials, nothing fighting, the quietest version of this light and the one that suits a period house. Against walnut it does the opposite — the dark timber pushes the brass forward and the whole thing reads as jewellery rather than joinery. Beech sits between the two, cooler and paler, and lets the brass be the only warm thing in the frame.
Match the bulb holder to the arm and you get the traditional version, all one metal. Give it a copper holder and it warms further; give it chrome and you get a deliberate two-tone that people notice from across the room. All three cost the same, so the choice is entirely about the room.
If you were searching for antique brass wall lights, this is worth knowing: ours is bright, polished brass — a modern brass wall light, not a factory-aged one. It arrives with the shine on, and against the wood that is the point: the plate supplies the age and the warmth, the metal supplies the light. If you would rather it mellowed, real brass does that on its own with time and handling, which no sprayed-on antique finish can honestly claim.