The stairs leading to my unfinished basement are a bit dark. I'd like to add a simple light fixture to brighten them but I don't know the best place to put it to minimize shadows and glare. Above the door? In the ceiling? At the foot of the stairs? On the wall? I've searched the web for a while and I can find code about when you need a light and where the switches need to be but can't find a best practice for fixture placement.
Why one fixture?
No matter where you put it, a single fixture can result in a range of illumination, from bright glare to dark shadow. Consider at least two fixtures, one slightly down from the very top of the stairs, and one or more between the mid point and the bottom.
If installing on a flat ceiling, use floods or spots rather than conventional bulbs. These point downward and lessen glare at the top of the stairs.
If you are installing in a sloped ceiling, consider using recessed cans with angled trim. This ensures that the light beam points downward, even on a sloped ceiling, and not toward the descending person's eyes.
You could illuminate the stair treads themselves with recessed step lights: http://www.homedepot.com/p/Halo-9-in-White-Recessed-Lighting-Step-Light-H2920ICT/100137286
If you want simple, one light at the top of the stairs above the door, whether on the wall ceiling. It will not blind you on the way down and on the way up, the persons eyes are usually focused on the treads in front or the bottom of the opening the stairs lead to. It would take some hard looking up the stare into the light, unless you are a deer.
If you want fancier, 2 wall sconces that are closed at the top so you do not see the bulb on the way down, spread across the wall on the first quarter and the last quarter. That is looking as the wall as if the wall space was divided up into 4 equal sections, about 6 1/2' above the run of the treads if the ceiling allows it.