Comprehensive, soothing but perhaps a shade too peaceful, "Claude Lorrain: A Tercentenary Exhibition" opens Sunday at the National Gallery's east wing. The spontaneous drawings outshine the sunlit landscapes, which are almost oppressive in their harmony: There's not a rain cloud in sight.

The 53 paintings, 76 drawings and 88 etchings, on loan from around the world, are stately and grand, and cover the gallery's bottom floor.

Mainly, Claude was awed by natural light, Rome's glow in particular. His landscapes are idealized, along the lines of Raphael but editing out such dramatic elements as lightning or storms. His seaports, too, are clean and shimmering in perfect sunlight. Tranquility and serenity prevail: Water laps gently at the shore; men and animals frolic in fields where it's always fair.

He mined myths, history and the classics to come up with such placid scenes. For the churchmen among his patrons, he turned to religious works. He'd never seen Delphi, but his two renderings conformed to ancient literary descriptions. His themes were noble, from "The Judgment of Paris" and "St. George and the Dragon" to baby Moses. Often his subjects are seen taking off on voyages or journeys into the light (a popular 17th-century metaphor for what's now called "passages"), with the sun a metaphor for all that's good or at least still possible.

It's clear from this exhibition why Claude Gelle, called Lorrain after the duchy of his birth, is best known to modern viewers for his drawings. While his paintings are impeccable and his etchings significant experiments with changing light in black and white, the drawings are most affecting. They're less formal, more believable. The act of creation is evident in the artist's more urgent sketches.

With more than 1,200 sheets to choose from, the drawing section was the more selective. The result is a variety of rapid sketches from nature; compositional sheets (some unfinished); animal, tree and figure studies; drawings preparatory for paintings and records of completed paintings. Several media are represented, including pen-and- ink, brown wash, black chalk, white body color and white, buff, blue and pink papers.

A number of drawings have incomplete sketches on the reverse, which aren't exhibited. But two sheets are hung to show both sides. "Abraham Expelling Hagar and Ishmael," actually two complete compositions for a painting, reveals that Claude traced the drawing from one side to the other by holding it up to the light. He then made several changes in details for the final painting without departing from the specifications in Genesis.

CLAUDE LORRAIN: A TERCENTENARY EXHIBITION: At the National Gallery, east wing, through January 2.