Most hidden lights consist of three components. The housing is the enclosure hidden in the ceiling that contains the electrical wiring and socket for the fixture. The trim is the only visible part of the light and varies by light style. Most trims are not interchangeable among recessed light fixtures. Bulbs for hidden lights vary in wattage and coatings to create various levels and types of illumination.
The best trim for recessed lighting depends on the desired effect. Reflective clear or black trim reduces the most glare from the light bulbs. Flat black trim is less reflective and more economical, and flat white trim is less visible when the lights are turned off. Sloped trims create a ray of light perpendicular to the floor. Recessed shower trim is specially treated to resist water and moisture. Wall wash trims use a reflector to diffuse the light evenly on wall surfaces.
After you pick the trim for the recessed lights, roughly sketch out the design to calculate how many lights you need for each room and their location. Hidden lights should be at least two feet from the surrounding walls to prevent glare. Avoid mixing in hidden lights with multiple conventional light fixtures, as their effect will be lost if brighter lights overpower their subtlety. If there are other light sources in the room, such as table lamps, halogen floor lamps and fireplaces, consider how they will impact the visual effects of the recessed lighting.
The placement and light bulb voltage create varied effects in hidden ceiling lights. If you have standard 8-foot ceilings, install 6-inch recessed lights about seven feet apart. To accentuate small pieces of art or sculptures discreetly, use a 4-inch low-voltage lamp for each item and increase the number of lamps for larger pieces. For tall trees or statues, install hidden lights that cast light at opposing angles on the objects to give depth to their appearance. If the hidden lights are used over desks, place them in the ceiling a little behind and off to one side to prevent casting a glare on the desktop.