Despite the abundance of color in Hilda Thorpe's surprisingly fresh exhibition of paintings at Gallery K, the show's title, "Color as Content," is misleading. The show is much more than just an exploration of pigmentation. It's a brief history of one artist's quest to create a hybrid style by crossing two central elements of American postwar art: color field painting and abstract expressionism.

Thorpe has been pursuing her distinctive artistic visions in a variety of media since she first emerged on the Washington art scene in the 1960s, showing at the Jefferson Place Gallery, a hotbed of the Washington Color School. But even early on, she couldn't be classified simply as a Color School adherent.

Although she was influenced by Color School techniques such as staining unsized canvas with thinned-out acrylic paint, Thorpe displayed a willingness to experiment with other methods and media. Contrary to stain-painting orthodoxy, she sometimes used the kind of gestural brush strokes that could be found in the paintings of Willem de Kooning and other leading abstract expressionists.

While the love of vibrant color has been a constant in Thorpe's long career, her fondness for experimentation appeared to have waned in recent years as she focused on creating abstract, acrylic paintings on self-made paper. While often quite pretty, they also seemed dull and dated, like tepid throwbacks to the Color School days.

So much for appearances. At age 80, Thorpe has produced some big, masterly new oil paintings filled with light, energy, color and commotion. It's as if she walked into the studio one day and decided to just paint from the gut and see what happened. Whatever her motivation, the results are a delight. On one canvas, the glowing midsummer colors of Monet's garden at Giverny seem to have been boiled down to their essences and then applied with a flurry of bold, slashing brush strokes. On another, the pigment is as thick as toothpaste straight from the tube.

In "Time and Again," a large oil from 1999, the paint is so thinly applied that you could count the threads in the canvas. But it's applied with broad yet delicate brush strokes that seem to evaporate before your eyes. By contrast, "Opening Up . . . ," another 1999 oil, features thicker layers of paint that seem to be in motion, flowing across the picture plane.

The exhibit also contains a few interesting anomalies, such as the loosely figurative watercolors that Thorpe did on a recent trip to Morocco. While they don't rank with her large oils, they are lovely, evocative little studies. More compelling are the small, abstracted landscapes that Thorpe painted with black wash on paper in 1978.

Maybe it was the stint abroad that sparked the sudden outburst of painting. Or maybe Thorpe decided there was still more to harvest from her hybrid style. Whatever the reason, it's a colorful return to form by a very fine painter.

Patrick Craig at Gallery K

Gallery K is also showing recent paintings by Patrick Craig, who creates abstractions that mix anthropomorphic, geometric and representational elements with a kind of Escher-like interweaving of figure and ground.

In his previous exhibition at the gallery, Craig's work seemed rather cool, formalistic and flat. But this latest batch of works, painted over the past three years, is just the opposite.

By using brighter colors, in some cases bordering on Day-Glo, he makes even monotonal works, such as the explosively red "Bloom," exude a kind of welcoming warmth. The eye-catching color pulls you into the work, where Craig's deft manipulation of space and form takes over.

There's considerably more depth of field in these paintings, compared with some of his previous work, and Craig uses the expanded space to play all manner of fool-the-eye tricks. What looks like an African mask suspended in space in front of a pastoral scene suddenly morphs into a lantern. Then it turns into a hollow shell that once housed a space alien, before evolving into a purely geometric abstraction composed of circles and ellipses.

It's strange, but appealing stuff: quasi-geometric abstraction in warm colors mixed with dashes of Star Trekkian fantasy and art-historical references. The shifting images are impossible to pin down, but it's a lot of fun to try. There's nothing formal about that.

'Forces of Nature' at Kathleen Ewing Gallery

Earth, air, fire and water could be the name of some knockoff funk band. But in this case those are the subjects of "Forces of Nature," the anti-millennial madness show at Kathleen Ewing Gallery, which features the work of six photographers.

Looking at the pictures of our world taken by Len Jeshel, Diane Cook, Alex MacLean, Judy Sanchez, Bruce Barnbaum and Frank DiPerna is refreshing in part because it puts man in his place.

Compared with the Earth's physical majesty and duration, we're puny, short-lived little creatures who spend much of our time messing up the most beautiful planet in our solar system. Even our art isn't all that original. DiPerna in particular seems to delight in photographing natural phenomena that look remarkably like abstract paintings.

Some of the photographers work in black-and-white, some in color. But each of them has a unique and reverential take on the world around us. Let's hope some of nature's wonders, such as glaciers and forests, are still here when the next millennium rolls around.

Hilda Thorpe, Patrick Craig at Gallery K, 2010 R St. NW, Tuesday-Saturday, 11 a.m.-6 p.m., 202-234-0339, through Jan. 29.

Forces of Nature at Kathleen Ewing Gallery, 1609 Connecticut Ave. NW, Wednesday-Saturday, noon-5 p.m., 202-328-0955, through Jan. 29.

CAPTION: Patrick Craig's "Pillow Horns," left, and "Reveille" at Gallery K: Shades of Escher.