"When I talk about frames I can almost never eat lunch," says Stanley Robertson, frame conservator at the National Gallery, his eggs benedict ignored and growing cold. "I'm afraid that, as far as frames go, I'm a hopeless romantic."

Robertson, 46, speaks softly, with just a slight accent from his Scottish homeland. He has lived in a montage of places from Hong Kong to Paris, and has had successful careers in music, painting and woodworking. But from the day he discovered frames, he has dedicated himself to studying and conserving them. "What I'm trying to do," he says, "is to use the knowledge I have to lengthen the life of a frame. The trouble is that the knowledge I have is never enough."

The importance of frames in the art world is much greater than the average museum-goer might realize. "Most people look at one or the other . . . The idea is to have a beautiful painting and a beautiful frame together so that they are harmonious."

Frames play a crucial role in the presentation of paintings, both esthetically and functionally. "One of the things a frame does is separate a painting from its surroundings," says Robertson. "This gives a painting a finished quality. Every painting should have a frame. That is not to say that every painting should have a large gilded frame . . . Modern paintings speak for themselves, and they don't need much of a frame.

"One of the problems with paintings in museums is that they are often shown in a setting different from their original one," he says, adding that the decor of the room where the frame will hang is important in making a frame. "The color of the walls, the type of furniture, these things give me an idea of what kind of toning to use."

Framemaking is an art form, says Robertson, who studied gilding in Paris. He was also a painter for eight years and believes his artistic training has contributed significantly to his work as a conservator. "If you have no idea about paintings, then how can you understand frames?" he asks, then reminds one that Rembrandt sometimes designed his own frames, which are works of art in themselves.

He conserves and reproduces frames from many different periods and finds it difficult to name his favorite style. "I think probably the area I am most interested in presently is the Dutch 16th and 17th century, the gilded frames. The Dutch were avid seamen, and they brought back designs from Italy and wonderful woods from Africa . . . Italy was responsible in the early Renaissance for the spread of beautiful designs and innovative styles."

The Italians may have refined and improved frame design, but the concept of frames goes back at least as far as the cave men. Paintings with frame-like drawn borders have been found on cave walls. Egyptian hieroglyphics almost always have borders.

Frames arrive in all sorts of conditions at the National Gallery. In the conservation workshop, its walls decorated with paintingless frames, Robertson quietly battles the main enemies -- water damage, age and lack of proper cleaning.

If the wood of a frame has shrunk, he gives it a hot bath in size, a type of glue. This swells the wood's fibers back to their original size. If he decides to change a frame he is working on, he is sure to preserve its historical correctness. This includes matching wood types, designs and techniques.

Because Robertson puts so much time and care into each, he tries to "keep a watchful eye on the life of a frame." He has been able to keep track of many, which hang in such notable places as the Louvre, the Palace of Versailles, the Metropolitan Museum and, of course, the National Gallery.