The first thing we did when we reached our study this evening was go up on C-Span to watch the unveiling at the White House of the portraits of President George W. Bush and Laura Bush. It was a wonderful occasion, at which President and Mrs. Obama could not have been warmer and more gracious and the former president more charming. He noted that the collection of White House portraits now begins and ends with paintings of presidents named George W. He was standing in front of the painting of Washington that had been saved by Dolley Madison when the British burned the White House. “Now, Michelle, if anything should happen,” Mr. Bush said, gesturing toward his own portrait, “there’s your man.”

It’s a marvelous portrait, and when we heard that it was painted by John Howard Sanden, we looked immediately at the nose. For some years ago we made a habit of going to Mr. Sanden’s annual demonstration at the Art Student’s League on 57th Street in Manhattan. It was always sold out, as aspiring painters (and no doubt some well-established ones) crowded in to see how Mr. Sanden created his likenesses and did so in under a couple of hours. Mr. Sanden would enter at exactly 8 p.m. He might talk for a moment about the man who first hired him as a staff painter, the Reverend Billy Graham. Then he would get to work with astounding efficiency, and his sitter would soon come into view on the canvas.

As he painted, Mr. Sanden talked a good bit about one of his heroes, John Singer Sargent, noting — we’re writing this from recollection — that when Sargent painted he made a practice of holding in his right hand the brush and in his left hand a plumb line. The White House collection includes one of Sargent’s greatest portraits, of Theodore Roosevelt; a copy of it hangs in the Harvard Club of New York. It happens to be our own favorite of the White House portraits, although Aaron Shikler’s portrait of President Kennedy, with his arms folded across his chest and looking downward in thought, is a contender.

In any event, one of the things that Mr. Sanden taught was the importance in portrait painting of the highlight at the end of the nose. The nose itself is always a test, and part of the test is getting it to “pop,” meaning to appear to come out from the face. It’s harder than one might imagine. One can try red on the side of the nose, though it’s but one trick. The last trick in getting the nose to pop has to do with the highlight. It seems — or so we recall Mr. Sanden asserting — that every human nose has that highlight at the end. Mr. Sanden also used to tell his students that the great portraitists made a game of trying to place that highlight by standing back from the painting, holding the brush out with an extended arm and placing the highlight with a single flick.

And when the George W. Bush portrait was unveiled, there it was, just as Mr. Sanden had lectured. The nose popped. Some red — probably cadmium red light — is on the right side of the nose (Mr. Bush’s left side), just as Mr. Sanden had lectured his students. And there at the end of the presidential proboscis, a highlight that could well have been placed with a single deft flick by one of the master portrait painters of his time. Expressing his pleasure at the portrait, President Bush elicited a laugh when, addressing Mr. Obama, he said: “I am pleased, Mr. President, that when you are wandering these halls as you wrestle with tough decisions, you’ll now be able to gaze at this portrait and ask, ‘What would George do?’” This is the way presidents frame our national memory, by being framed in the house they lived in. What a rich and warm tradition, so beautifully extended today.