Douglas MartensonThrough May 31, Gross McCleaf Gallery, 127 S. 16th St., 215-665-8138

Once long ago when I still enjoyed camping, a friend and I traveled west. We lost our tent to a storm in Utah. One afternoon in Southern California we tied our tarps a few trees down from some sociable folk who were traveling in their van. Later, when the rest of the campground was quiet, our neighbors dropped by our campfire with beer and refreshments. They were easygoing people who acted in porn movies. One revealed that a director had told him that he could have been a star in mainstream films if not for an unfortunate ingrown hair on his chin.

We soon began to feel the lack of music. Strangely, no one had a radio or tape player. The ingrown hair guy decided to entertain us. With utter conviction, he whaled away on an air guitar while explaining what we would be hearing if he actually had a guitar and knew how to play it. "I'll start out with some chords real loud: ŒWhroom! Whroom! Whroom!' Get me some feedback: Œr-rNNNNr-rNNNNggg.' Can you hear it? The drums are going: ŒDOOM da doomdy duh duh doomdy doom DOOM!' Now here comes my solo. ..."

You get the idea. He played a long solo that would put Jerry Garcia to shame (or so he said).

Ah yes, I thought, with a torpid thrill of recognition, this is conceptual art. At least, it's not real loud.

In a recent New Yorker article, Calvin Tomkins quotes the Dean of Yale's School of Art, Richard Benson: "There's a lot of conceptual art around today because it's easy. It's much easier to think about something than to make something." One facet of conceptual art, Tomkins and Benson agree, is that it tends to be art not about the world but about art-making.

Art can't help being somewhat self-referential. That's how we know it is art, part of a tradition. But sometimes, caught up in the arid talky air guitar of conceptual art, one begins to fear that the juicy material disciplines of art making -- practices rooted in all cultures, many of which developed over millennia -- are endangered species.

Hard-to-master skills remain a hallmark of craft arts. As for painting, in Philadelphia, sometimes considered a bastion of realism, only a minor contingent of galleries like Gross McCleaf, More Gallery and F.A.N. consistently honor the ability to represent things in paint.

The current show at Gross McCleaf demonstrates -- if we need reminding -- that representational painting is not merely alive and well but serious, substantial art. David Shevlino's deft depictions of natural light and glowing color are in the front gallery, near the windows. The cool light explored by Douglas Martenson, a more "northern" draftsmanly artist, who is showing mostly interiors, works nicely in the back gallery.

Shevlino applies carefully chosen color in broad soft brushstrokes, saturated and velvety with little frayed edges flicked up by the corners of his brush (curiously linking his painting to Barnett Newman's ragged-edged zips currently at the PMA.) The rim of a bowl in Melon Slices gleams with white angular flecks, creating a paradoxical sense of clear edges without sharp definitions, a kind of painterly fuzzy logic. What we see in Shevlino's painting is not the bowl but light bouncing off it. Not a variation on impressionism: This is form described by precisely shaped color. Shevlino's cantaloupe slices reflect and absorb light into succulent red centers. The green border joining skin and flesh is translucent.

Even this artist's pictures of gray highways under gray skies manage to record how marvelous the gift of sight is. And his purple-shadowed arched bridges (there's only one in this show) remain the best in Philly.

Martenson's body of work revolves around a lamp and two chairs. The lamp appears in eight paintings, as I recall. Martenson seems fascinated with the arc of light it casts above and below the ivory shade, though he also shows the shade of the unlit lamp penetrated by exterior light from a window.

There's a subtle exploration of pictures portrayed within pictures. Although one is a mirror reflecting the artist full-length at work on a canvas, Martenson seems not so much interested in the content of the pictures as in their frames' compositional roles. The implication that the painting you are at that very moment enjoying may soon be relegated a similar compositional place-marking is amusing.

Gross McCleaf displays a selection of paintings from past and future shows in its top floor. There you can see Rose Naftulin's expansive gay outdoor flower pieces. A couple of Christine LaFuente's remarkable still lifes unite painterly immediacy with a Zen-like minimalism. Painting like this reminds us how impoverished our culture would be if we jettisoned a great tradition simply because it is possible to make art without having mastered its skills.

As for non-or-beyond-retinal art, I must admit that the naive conceptual campfire concert remains in memory, like much conceptual art, as a meaningful and quintessentially human event.