La Gioconda

#15 Last story The Sixth Person

"Amazing, unbelievable. I can't believe there was such a trick. Oh Leonardo, who the hell are you?"

　I was completely overwhelmed.

"Yes, there must be more. There are mysteries, many mysteries in this painting that have not been unraveled."

　I felt as if Leonardo's back, which I had once thought I could see, was now far away again.

"Oh, sister! Sis!"

"What's wrong, lua?"

"I wiped the surface of the frame with a handkerchief and the wing disappeared."

"What?"

　In a panic, I looked at the surface of the frame and found that the wing that should have been there were gone.

"What is this all about ......?"

"There was a lot of dust on the surface, so I decided to clean it up and take a better look."

"Dust? You mean a layer of dust?"

"Sorry, sister."

"Don't worry so much lua, this could be a new discovery. Maybe this means that the painting needs to be layered with a thin layer of something else. I see, the wings looked rainbow-colored earlier because of the structural color principle."

"Structural color?"

"They are colors produced by the interference oflight through a microscopic surface structure or thin film. For example, the back of a DVD, which itself is not colored, appears to be vividly colored, doesn't it?"

Lua was depressed and did not reply. But I tried to put the situation in perspective for the time being, despite my sister.

　If light was being interfered with by a thin film, the thin film in this case could only be a layer of dust, the transparent sheet of the picture frame, and the layer of air between the transparent sheet and the picture. Are all of these necessary, or can they stand alone ? Or do they need to be combined ? Or do we still need some other layer ? And how thick are those layers ? In addition, perhaps the type and intensity of the irradiating light may have something to do with it.

　How can we reproduce that? There are no more dusty picture frames in this house. So we just have to wait for the dust to settle on the frames again? But that would take too long.

"lua, you, can't you reproduce it on your computer using image processing software or something? You studied digital art in art school, right? Hey, lua, are you listening to me?"

"...... Now the angel wing, one after the other, he does that a lot."

　It was a little hard to hear, but my sister certainly mumbled it.

"Sister, I have a question for you."

"What is it ?"

"When did he finish this painting?"

"What? No, apparently it's not finished yet, as far as I can tell from what I've found on the Internet." [Note1] [Note42]

"Unfinished?"

"Maybe that's why, after all, Leonardo never gave this Mona Lisa to his client, Bartolomeo." [Note1][Note43].

　Lua's eyes sharpened for a moment.

"...... what is he doing ? This guy."

"What ?"

"Didn't finish it? Couldn't give it to Bartolomeo? It's not natural! There's no way he could finish it in a decent way with all this elaborate stuff he has been doing! Or rather, there's no way he could have handed it over in the first place. Because it's probably already quite different from the original Lisa's face, and her husband would say, Who is this woman? This is not my wife! And then Bartolomeo will turn it over to him."