A great table lamp can have an outsize effect on a room.

Even in a space that has been thoughtfully designed, from the carpets to the curtains, it’s often possible to point to a single element that takes it all to another level. And more often than not, “oddly, it’s the lamp,” said the interior designer Steven Gambrel.

That’s why Mr. Gambrel is always on the hunt for exceptional lamps at flea markets and antiques stores across the United States and Europe. “I love odd shapes and glazes, and I prefer lamps with height,” he said. The large-scale ones he likes, he adds, are frequently ceramic or blown glass.

Occasionally, he turns vintage finds into lamps that he uses in his projects. “Right now, I’m wiring a Japanese bronze vessel,” he said. “Sometimes we use large 19th-century glass bottles — which are great for beach houses — big, mirrored mercury-glass vessels or old apothecary jars.”

But whether a lamp is new, antique or a D.I.Y. creation, what matters is that it’s an interesting shape or color, Mr. Gambrel said: “It really helps give that extra spirit to the decorating.”