BUNNY WILLIAMS, the no-nonsense decorator known for her lush English-style rooms, is laying in light bulbs like canned goods. Incandescent bulbs, that is — 60 and 75 watters — because she likes a double-cluster lamp with a high- and a low-watt bulb, one for reading, one for mood.

“Every time I go to Costco, I buy more wattage,” Ms. Williams said the other day. She is as green as anybody, she added, but she can’t abide the sickly hue of a twisty compact fluorescent bulb, though she’s tried warming it up with shade liners in creams and pinks. Nor does she care for the cool blue of an LED.

It should be noted that, like most decorators, Ms. Williams is extremely precise about light. The other day, she reported, she spent six hours fine-tuning the lighting plan of a project, tweaking the mix of ambient, directional and overhead light she had designed, and returning to the house after dusk to add wattage and switch out lamps like a chef adjusting the flavors in a complicated bouillabaisse.

She is aware that there is legislation that is going to affect the manufacture of incandescent bulbs, but she’s not clear on the details, and she wants to make sure she has what she needs when she needs it.