I have a window that doesn't get very much light. Perpendicular to it there is a wall of the house, which gets more light. I would like to put a mirror on this wall to get more light on that window. Is there any specific type of mirror to buy for this? In particular, is there something that withstands the elements well, and do I need a particular curvature for the mirror or a flat mirror?
You can get vinyl adhesive mirror film (often from theatrical stage equipment suppliers) whcih may be cheaper and more robust than glass mirror when applied to a suitable exterior substrate (eg plastic correx or foamex board)
A tinted mirror might reduce birds flying into it, and be aware that a mirror or lens reflecting direct sunlight onto furnishings has been known to start fires.