Randall Whitehead has spent more than a quarter of a century designing architectural lighting that beautifies people's homes and gardens. And for nearly as long, he's been living in the dark.

At the tender age of 25, after working for several years as a theatrical and television lighting designer, Whitehead founded San Francisco-based Randall Whitehead Lighting, Inc. He's since illuminated homes all across the country (including those of Bing Crosby and Jerry Garcia), and has written seven books on residential, commercial, and outdoor lighting. (Read more about one of his books on page 54 of the magazine.)

It's ironic, then, that his own home - on the lower floors of a three unit 1907 Victorian in San Francisco's Potrero Hill neighborhood - was, until recently, a dim grotto.

When Whitehead bought his building in 1983, he says, "the whole place was an absolute terror. Over time the back had settled a full nine inches, so you'd walk in and start going faster and faster as you trotted downslope."

Whitehead rented out the two upper units, which were in tolerable shape, and reserved for himself the truly dilapidated ground-level apartment. The bathroom floor was so riddled with dry rot that the toilet was sinking through. An exterior rear staircase leading to the basement-level garden had collapsed. Period lighting fixtures, he would discover, had been boxed in by the addition of dropped ceilings. And to top it off, there were exactly two small windows at the north-facing back of the unit; they framed tantalizingly tiny views of downtown San Francisco and admitted only the puniest dose of natural illumination.

"There was some light at the very front of the place, which faces south," Whitehead says, "but by the time you were in the entryway it was dim, and the dining room and living room [at the back of the apartment] were just plain dark."

It took years to get Whitehead's building into basic order. The rear of the sloping structure was hoisted, and the plumbing and electrical systems were overhauled. After that, Whitehead poured funds and energy into upgrading the rental apartments, planting a dramatic garden full of palms and ferns, and working his "electrical magic" on the interior of the unit.

In an effort to combat the darkness, Whitehead deployed an army of table lamps, pendant fixtures, wall sconces, recessed downlights, and ceiling-directed torchieres. He combined the fixtures in an approach he calls light layering, which uses the four different types of lighting - task, accent, ambient, and decorative - in a single space.

Each of the four elements is essential to creating a balanced effect. "If, for instance, you just use accent lighting in a room - picking out the orchid, the art, the coffee table - and you don't use ambient lighting, you get the "museum effect,' " Whitehead says. "It looks beautiful, but people start feeling tired due to the stark contrast between the light and dark areas. If you try to light solely with a decorative fixture like a dining room chandelier, you create a supernova look that's visually overpowering." If, on the other hand, you layer the elements, he says, "you can create a cohesive environment that's alive with light in a subtle way. And it makes people feel welcome - and look better. It's like plastic surgery without knives."

By layering the light, Whitehead was able to transform his apartment. After sunset, the rooms glowed with visual warmth and drama. But, Whitehead says, "I still wanted to make this dark tunnel as inviting during the day as it was at night." Finally, in 2003, Whitehead began planning a remodel with architects Laurie Erickson and Chet Zebroski, of Erickson Zebroski Design Group in San Francisco. He chose them, he says, not only because of the long relationship he has with them (they've worked on numerous projects together over the course of 16 years), but because "they understand how lighting and architecture work together."

Erickson and Zebroski created a plan that pushed the back of Whitehead's building out eight feet, encapsulating the rebuilt exterior staircase and two decks. Even more significantly, they called for the new rear exterior walls to be composed of two 24-foot-wide spans of glass.

"All of a sudden," says Whitehead, "all this light started to flow in. I was so invigorated by it that I began replacing all the solid doors in the house with sandblasted glass doors so that the light could continue to travel through.Then, for the same reason, I added glass blocks in the kitchen and shoji panels between the guest bedroom/study and the dining room; then I used mirrored walls to bounce light through the space. Finally, finally, I was getting the natural light I hadn't been able to get in the earlier remodels."

By adding eight feet of depth to the home and opening its entire back to the outdoors, Erickson and Zebroski helped Whitehead realize a very specific light-related dream. "Before this remodel, my bedroom had been in the middle of the house, where it was always dark," he explains. "I had always dreamed of waking up to daylight. At the last minute, [my interior designer] John Martin [of Turner Martin Design in Palo Alto] said, "Why are you staying upstairs, when you can now fit a master suite in downstairs?' So now my bedroom is against a wall of glass, and I wake up to light coming through a wide city view every day."

And long last, Whitehead has seen the light.