Photograph: Katrina Wittkamp

Guy on the Glow Well-lighted "amazing" bathrooms are a trend, says Xavier Yager, shown here with his canine companion in his own home. The Zen chandelier and Twin Tube mirror lights are from LBL Lighting.

Xavier Yager dwells in a world of shadow-and that’s the way he likes it. Yager, a lighting consultant at Lightology (215 W. Chicago Ave., 312-944-1000; Yager direct: 773-469-7283), takes shadows seriously. "The angles and shadows created by light create a three-dimensional look that punches up your whole interior. Most people live with flat lighting that drags it down," he says.

Uniform, shadowless lighting makes artwork disappear into its frame and the decorative details of a room fade away. Flat lighting is common in windowless stores and offices with ceilings full of fluorescent tubes; in homes, a single overhead fixture can flood a room with dull, even light.

Yager, a certified specialist with 15 years of experience, creates dimensional effects by combining general lighting with accent lighting. General lighting includes overall room illumination from traditional cans, recessed bulbs, chandeliers, or track lights.

General lighting might also involve a monorail-a half-inch track that runs around the perimeter of a ceiling, studded with subtle spotlights that can be angled to illuminate specific areas, which Yager refers to as "painting" with light. Accent lighting includes table and floor lamps, picture lights, and hanging lamps that punch up decorative details.

In a dining room, for example, he might recommend installing ceiling spots to send barely detectable beams that alight on a table, making silver glimmer and crystal gleam. "If you expect to illuminate a table with a chandelier, it will be very bright," Yager says. "If you put cans at opposite ends of the table and focus them on the table surface, you can bring the chandelier down to a lower level. It creates a whole mood and energy."

What about the bulbs? For Yager, there’s one choice: halogen. "In my house everything is halogen except for three pieces that are artistic," he says. "I hate fluorescent. If you use fluorescent with granite countertops, the granite goes dead. Use halogen, and the light hits it and you get depth and sparkle; it really changes the quality of the stone." Yager also likes xenon bulbs for under-cabinet lighting.

This lighting designer recommends installing dimmer switches wherever possible, and using them. Dimming lights by just ten percent can more than double the life of a bulb, he says. If glare is a problem with existing can lighting, install simple, nonreflective black liners inside the cans to decrease reflective glare, and "egg crate" baffles to diffuse light from too-hot spotlights.

Every room has challenges, Yager says. Entryways, which often feature a mirror, artwork, and/or unusual flooring-all of which can be lighted from separate sources for maximum impact-also need to be  filled with light for a parting glance in the mirror. Hallways that serve as galleries benefit from multiple spotlights.

In bathrooms, several sources are needed to properly illuminate work areas. Yager likes ceiling spots targeted on the sink, the commode, and the tub, with additional side lighting at the mirror for bright, flattering shaving and makeup light. A current trend in this room: large-scale chandeliers.

In living rooms, he prefers to reduce clutter by replacing floor and table lamps with ceiling lighting for high and midrange illumination; in some cases, well-directed ceiling lights can cast beams broad and bright enough to read by. Add picture lights to emphasize artwork, and a table lamp or two for reading and for decorative punch. Bedrooms have more appeal and less glare on the bed when lit indirectly. "You can achieve this with bedside lamps or retractable reading lamp arms."

The benefits of a properly lighted room go far beyond mere aesthetics, Yager says. "When you walk in at the end of the day and with two flips of the switch can light your way beautifully, it raises your mood," he says. "A perfectly lit home is a joy."