Nova (1974–…): Season 46, Episode 21 - Decoding da Vinci - full transcript

A visit to Florence, Italy to explore how Leonardo da Vinci used science, from human dissections to innovative painting techniques, to create his artwork.

Are you wondering how healthy the food you are eating is? Check it -
Leonardo da Vinci.

Legendary artist.

His genius is universal.

It speaks to everybody.

He was also a scientist
and inventor.

There was a reason
for every decision

and every line.

How did he create

the most famous painting
on Earth?

You can perceive the beating
of the pulse

underneath her skin.

The answers have been as elusive
as her smile.

Leonardo embraced mystery.

Now researchers are peeling away
the layers.

Thanks to a new kind of
scientific investigation,

we are really able to get
inside the painting.

Can science unlock her secrets?

She seems like she's alive,

because she looks different

depending on
where you're looking.

And decipher the genius
behind her creator?

"Decoding da Vinci,"

right now, on "NOVA."

Major funding for "NOVA"
is provided by the following:

In the heart of Paris lies
a former royal castle.

It is now the world's busiest
art museum:

the Louvre.

Filled with glorious galleries

of antiquities, mummies,
and Michelangelos.

But one masterpiece
is the biggest draw of all.

Today's reigning queen...

the "Mona Lisa,"
by Leonardo da Vinci.

The "Mona Lisa" has become

some grand thing
in our imagination.

Each time you see
the "Mona Lisa,"

you have a different feeling

about what she has in mind.

Every year, millions visit her,

drawn by her beauty

or, perhaps, her fame.

They've clocked the average
amount the visitors

spend looking
at the "Mona Lisa,"

and that's roughly
about 15 seconds.

You're more focused
on getting a good picture

for your Instagram feed

than actually
looking at the painting.

So is the "Mona Lisa"
just famous

for being famous?

More icon than art?

Or does she deserve her place
on the Louvre's throne

as the most celebrated painting
in the world?

It's not just a portrait

of a woman who was living
500 years ago.

It's a demonstration
of how painting could show life.

Now researchers are using
new techniques

to investigate the most famous
painting on Earth

like never before.

The smile is crucial.

It's teasing you, saying,

"I know something
you don't know."

Could the "Mona Lisa,"
with her enigmatic smile,

be the key to decoding
the man who made her...

Leonardo da Vinci?

No doubt he was
a brilliant artist,

but he was also
a groundbreaking scientist.

He anticipated theories
by both Galileo and Newton

by at least a century.

And dreamed up
remarkable inventions

that seem to predict
our modern age:

armored tanks,

flying machines,

even something
like a self-driving car.

But were
his scientific explorations

a distraction from his painting?

Or was science the secret
to his artistic genius?

Was the "Mona Lisa," in fact,
Leonardo's greatest invention?

If you want to understand
Leonardo da Vinci,

you just have to look
at the "Mona Lisa,"

because it's all there.

It's the culmination
of a lifetime spent

loving science and art.

In the back streets
of Florence, Italy,

Valter Conti
and his daughter Elena

prepare for their tribute
to Leonardo

and the "Mona Lisa"...

Human statues
handing out Leonardo quotes.

It's their way
of marking the 500th anniversary

of Leonardo's death,

and just one
of many celebrations

that are in the works
around the world.

From a fine art museum
in Beijing

to a multimedia extravaganza
in Peru...

And a blockbuster exhibition
at the Louvre.

For the Louvre museum,

it's a really important moment.

Because Louvre
is like Leonardo da Vinci.

We have the third
of all his paintings.

Vincent Delieuvin oversees
the five Leonardo masterpieces

that hang at the Louvre.

That's the largest collection
in the world.

While Leonardo may be

the most famous painter
of all time,

he completed surprisingly few

Leonardo was really
someone experimental.

He didn't want to paint a lot.

He wanted to paint
a perfect painting.

So what did it take

for Leonardo
to make a perfect painting?

The answer may be lying
right under Delieuvin's feet.

For the upcoming exhibition,

he is working
with a team of scientists

housed downstairs
from the Louvre,

at the Center for Research
and Restoration

of Museums in France.

Thanks to a new kind
of scientific investigation,

we are really able to get
inside the painting

and to understand
how Leonardo was working

to perfect the painting

for a long, long time...
during five, ten, 20 years.

It's really something
really specific to Leonardo.

They are peering deep inside
Leonardo's masterpieces,

hoping to reveal
the secrets of his technique

that our eyes cannot see.

The eye sees something

that it believes
to be two-dimensional,

but which is really

because there is depth
in a painting.

For art historian Bruno Mottin,

the first step is to understand

the chemistry
of Leonardo's paint,

starting with
the powdered minerals

that were the source
of his colors.

You have green, which is made

with the scratching
of copper plates,

you have vermillion,
which is made with mercury,

you have lead white,
which is made with lead.

But these can't be applied
directly on a painting...

it has to be mixed
with something else.

These colored pigments

are mixed with a liquid,
like oil.

That gets painted on in layers.

In a cross-section
of a painting,

you have the base-

which today
is frequently canvas,

but in Leonardo's time,
they used planks of wood.

On that is a coat of white
that can reflect light.

As the artist works,
semi-translucent paint

is built up layer by layer

and then sealed
with a coat of varnish.

In the end,
our eyes see the interplay

between the light reflected off
different pigments

suspended in the layers,

creating depth
and elusive subtleties.

Oil is a translucent medium,

which gives to the mixture
a deepness.

You can see through
all the layers.

You don't only see
a flat surface.

You have the feeling
of what is beneath the painting.

Leonardo worked on the
"Mona Lisa" for about 16 years.

Can these
investigative techniques

help reveal, ultimately,
what he was doing all that time?

The "Mona Lisa" began
in Florence, Italy, in 1503

as a commission
from a wealthy cloth merchant

to paint his wife,
Lisa Gherardini.

The word "mona" was
a polite form of address,

much like "madam,"
hence "Mona Lisa."

Over time, she became
something much more.

The "Mona Lisa" started off as
a portrait for a merchant's wife

and ended up as a sort of
manifesto, if you want,

of his ability
as a, as a painter,

of his conception
of the world, even.

So is this what the real Lisa
looked like?

And how different
does she appear today

from what Leonardo painted
500 years ago?

To find out, scientists
captured the "Mona Lisa"

with an array
of high-tech cameras.

These detect light
in the electromagnetic spectrum

that is not visible to our eyes.

So just as some cameras
can see wildlife in the dark,

these cameras can help us

see the "Mona Lisa"
in a new light...


Each image provides clues
about her past.

So we have a lot
of different images,

which can tell us

about the structure
of the painting

and the, the way
it has been made.

In the ultraviolet image,

blotches of dark blue appear.

These reveal areas of paint

which are not
by Leonardo's hand.

They are modern restorations to
repair damage to the painting,

like this dangerous crack
in the wood base.

And for Mottin,
it reveals even more.

It shows us that the painting
is in fact colored

by a greenish and yellowish

which changes the colors
of the true painting.

This thick varnish has
yellowed and darkened over time,

making it difficult
to make out some of the details.

She looks rather like
a plump lady, we should say,

because we do not know
where the arm stops.

But this infrared image
clearly shows

this dark area
was once translucent.

Lisa is wearing a veil

that gracefully falls over her
surprisingly slender shoulders.

To penetrate
the very deepest layers,

the team turn to a tool
more familiar to us

from a doctor's office:


These can reveal
how the painting began.

Most artists at the time
began with a drawing

and then filled it in
with thick paint.

So the X-ray looks like this,

Raphael's "La Belle Jardinière."

The figures started out
clearly defined...

and stayed that way.

But when Leonardo's paintings
are X-rayed,

the figures often vanish.

Leonardo image are like phantom.

We don't understand
at first sight

what really is on the picture.

In the X-ray of the "Mona Lisa,"
there is no clear outline.

Instead, the image evolved

as Leonardo made
continual adjustments.

This also suggests Lisa may not
have looked exactly like this.

He keeps it.

He doesn't deliver it

to the merchant
who commissioned it.

Because for him,

it's no longer
a portrait of Mona Lisa.

It is a universal painting.

In the upcoming exhibition,

Delieuvin plans to hang

some of these
scientific masterpieces

along with Leonardo's
original paintings.

The scans prove
an essential point

about Leonardo's artistry...

he painted like no one else.

Leonardo is one
of the first artists

to be really free.

He felt free to change his mind,

not only during
the drawing preparation,

but also during the painting
of his work.

This is incredibly not common.

He is the only one to give
such liberty, free manner,

in his execution.

Artists then were considered

and needed to churn out
paintings for patrons.

So how did Leonardo
become such a free spirit?

From the beginning,
Leonardo was an outsider.

Born in 1452
to an unwed farm girl

in the small Italian town
of Vinci,

he was named
"Leonardo from Vinci."

Therefore, Leonardo da Vinci.

Leonardo had
the great good fortune

to be born out of wedlock.

It meant he didn't
have crammed into him

the sort of old dusty scholastic
wisdom of the Middle Ages.

he got to be self-taught.

It also meant he didn't have
to be a notary like his father.

And so he has a fresh life,

where he can be
anything he wants.

At about 14, Leonardo's father

sent him to learn a trade
in Florence,

the epicenter of commerce,
learning, and beauty

at the beginning
of the Renaissance.

Florence was one
of the most advanced

social organization
of the planet.

Very wealthy city.

A city that was attracting
the brightest guys around.

Florence is just extraordinary
at this time,

to produce Donatello, Masaccio,

Michelangelo, Raphael.

With no formal education,

Leonardo started
as an apprentice

in one of the leading
artist's studios of the day:

the workshop
of Andrea del Verrocchio.

was a sculptor above all,

but also a painter,
an architect.

He could play music.

So the example of Verrocchio
was very important

to Leonardo.

Leonardo's training
with Verrocchio

is a real model
of how an artist should evolve.

Technique is subordinate
to the act of seeing.

It's about the eye,

and it's Leonardo
who first described that.

It is believed
the handsome model

for this Verrocchio statue
of David

is his apprentice,
a young Leonardo.

So, they think that
Leonardo posed for his master.

It's a very elegant boy face

framed by these beautiful curls.

Despite the circumstances
of his illegitimate birth,

the workshop gave Leonardo
a way to get ahead in life.

He's a misfit.

He's illegitimate.

He's gay, he's left-handed,

he's a vegetarian,
he's distracted,

and yet he's embraced
by the people of Florence

because it was
a very tolerant city.

One of the most challenging
construction projects of the day

was capping the dome of the
breathtaking cathedral

with a golden sphere.

The commission of the crowning
of the cupola

with a gilded sphere

was a very important one.

And that's a commission
that Verrocchio secured.

Verrocchio's team, which
included a young Leonardo,

had to figure out
not only the design,

but also how to secure
the one-and-a-half-ton ball

on top of the nearly
370-foot high cathedral.

Figuring out how to get the ball
on top of the cathedral

helps Leonardo become
a great engineer.

It helps him become an artist,

because he gets the perspective
of the ball right.

That combination of science,
engineering, and art

becomes part
of who Leonardo da Vinci is.

In fact, in sheer quantity,

scientific investigations

far outweigh
his output of paintings.

The proof of that lies
in a remarkable collection

of replicas of his notebooks.

We have very few records,

in the whole history of science,

to Leonardo's manuscripts.

These are not books.

You cannot compare that
to a work

of, by Galileo or by Newton,

because they have
solved the problems

before writing their books.

Paolo Galluzzi is the director

of the Galileo Museum
in Florence.

What we have in Leonardo

is the direct expression
of his internal dialogue.

Leonardo's notebooks
span his lifetime.

They even come pocket-sized.

We're sure that
those 6,000 pages that we have

are by him.

And this is just one-fourth
of what he actually penned.

So we're talking about
something he was obsessed by

throughout his life.

The brilliance and breadth
of Leonardo's notebooks

is astonishing.

His ideas seem to predict
our modern age,

making Leonardo much more
than a Renaissance scientist

for many.

His dreams of human flight

include a helicopter-like

and a parachute.

A fascination with water

led to ambitious
civil engineering proposals.

And he conceived an intriguing
self-propelled machine

that seems part-automobile,
part-early robot.

But could any of these inventive
designs have actually worked?

Leonardo is, of course,

a great artist,

but he's also a great scientist,

and, I would argue,
a great engineer.

The geometry is stunning...

One small sketch
in Leonardo's notebooks

has so intrigued M.I.T. engineer
John Ochsendorf

that he asked
his graduate student Karly Bast

to bring 21st-century
engineering rigor

to see
if Leonardo's 16th-century idea

would in fact stand.

There is a historical reason
for this,

because you see it
in the drawing, right?

Yeah, these two aren't...

In 1502, the year before
starting the "Mona Lisa,"

Leonardo proposed

to the sultan
of the Ottoman Empire

a bridge in Constantinople
five times longer

than any other span at the time.

His plan
for this ambitious project,

sketched upside-down
in a small notebook,

offers few details...

yet just enough for Bast
to bring it to life.

Leonardo provided
four measurements,

but he provided two sketches.

At first, it seems
like a rough sketch,

but as I dug into it,

I realized there was a reason

for every decision
and every line.

There was a lot of thought

put into the force distribution,
and it wasn't just aesthetic.

It was engineering.

And to test that engineering,

Bast and her colleagues

have built a scale model
of the bridge

with a state-of-the-art
3-D printer.

Before 3-D printing came along,

we'd have to try
to build that bridge

as close as we could
to the full scale,

because you couldn't reliably
get the geometry quite right.

Leonardo's stone bridge
would have been

500 times
the size of this model,

but the physics
are exactly the same.

We have the bridge,

and we have the mold
that's holding it up.

The first piece
should be easy to take off.

Piece by piece,
she removes the Styrofoam...

a modern day stand-in
for the wooden scaffolding

used in Leonardo's day.

This is more like heart surgery

than bridge construction.

Finally, the last support
is removed.

And Leonardo's stone bridge

The geometry is
aesthetically beautiful,

and the fact
that this is standing on its own

tells us that it was feasible.



Leonardo's bridge even stays up

when they simulate
an earthquake.


1,500 pounds.

Oh, my God.

It has moved by 30 feet,
and the arch still stands.

The bridge does eventually

but only after being moved
the equivalent of 50 feet.

Leonardo has
the artistic ability,

and he also has
that scientific knowledge

and that engineering capability

where he can create things

that are beautiful
and structurally sound.

Bast clearly had to fill in
some details

to get from this sketch

to this model.

And we don't know if the bridge
could have been built

with the wooden scaffold
of the day.

And he also shows...

But she has shown

Leonardo got the basic physics

What's extraordinary
is the ideas

that he was coming up with
more than 500 years ago.


We're still trying
to understand them.

As with this ambitious proposal
to the sultan,

Leonardo sought out
wealthy patrons

throughout his life

to support not only his art,
but his scientific explorations.

At 30, he moved to Milan
to work for its duke.

17 years later,
when the duke was deposed,

Leonardo had to move once again,

back to Florence,
and later, Rome.

His accomplishments
in science and art

meant he had much to offer.

Leonardo sells himself
as an engineer,

as well as an artist,

because he knows he can make
a better living.

But also, I think,
Leonardo just loved

the connection
of the arts and sciences,

and he didn't want to have
to be siloed as just a painter.

Leonardo's explorations
in science

can also be clearly seen
in the details of his paintings.

He studied everything
from botany

to the physics of flowing water.

Even the curls of human hair.

To paint something
absolutely perfect,

he had to understand
how nature was done.

To paint a mountain,
to paint rocks,

he had to understand
why the rocks were of that kind.

He was obsessed with that.

And that was what he called
the science of painting.

The science of painting was
all-encompassing for Leonardo.

But how could he capture
the beauty he observed in nature

with paint?

Back at the Louvre,
art restorers and researchers

are uncovering new clues

in an elegant
intensive care unit

for priceless works of art.

To prepare
for the upcoming exhibit,

Delieuvin and
the team of scientists

are restoring a painting
long shrouded by controversy.

For centuries,
this portrait of Bacchus

was considered one of the few
paintings by Leonardo's hand.

But now, experts aren't so sure.

For centuries, that painting

was attributed to Leonardo.

But during the 20th century,
some historians said,

"Well, it looks like difference

to the other paintings."

Cinzia Pasquali has been
brought in

to restore the painting.

Can Leonardo's
unique scientific techniques

provide the clue she needs
to finally solve the mystery:

did Leonardo in fact paint this?

Restoration work is not
for the faint of heart.

This painting may be
in bad shape,

but Pasquali
is still taking her scalpel

to an irreplaceable masterpiece.

She scrapes away
the yellow darkened varnish,

revealing a vibrant color

But other parts of the painting
appear more damaged.

So Pasquali must rely
on her training

not only in art history,

but also chemistry.

The colors of pigment in paint

can change or fade over time.

But the chemistry
of the pigments themselves

can still be detected.

Pasquali orders a special scan
for the element copper,

often used in green paint.

The scan reveals this dark area
of the painting

was once a lush garden,

until the copper in the paint

So we can see a lot

of vegetable and leaves
and plants and flower,

and when you look on the surface
of the work, they are not.

While the beauty of these plants
may suggest

Leonardo's meticulous attention
to detail,

that's not enough to say
for sure

he painted it himself.

So the investigation turns

to his brushwork.

One of the most characteristic
fingerprints of a Leonardo

are remarkably thin layers
of paint,

which can only be seen
with a powerful microscope.

Some Leonardos have been found

to have as many
as 30 layers of paint...

many more than most painters.

As she continues
her restoration,

Pasquali is looking for evidence
of this unusual technique.

But what was Leonardo
trying to achieve

with all those thin layers?

Just ask a living painter.

Da Vinci was always looking
for beauty.

He's not just painting
or drawing a tree.

He wants to paint the perfect
expression of what a tree is.

This aspiration
to beauty is, to me,

very inspiring as an artist.

Florent Farges is a painter
in Dijon, France.

In the tradition
of the Renaissance,

Farges runs
an artist's workshop,

but with a twist.

Hello, everyone,
and welcome to a new video.

His is a virtual one.

This one is going to guide you

through the entire process
of classical figure painting.

Most Italian painters
at the time

mixed their pigments
into an egg base,

using real egg.

But egg tempera doesn't allow

as much light
to pass through it,

so there is less depth
in the painting.

Instead, Leonardo decided
to use an oil,

like linseed or walnut.

Leonardo was using oil.

Because oil helps
to reproduce in the best way

the transition
between light and shadow.

Gradually, Farges' portrait
comes to life.

For the finishing touches,

Farges demonstrates
how oil paint

can be applied very thinly

to create
a subtle shading of light

falling across the human body.

If I want, I can come back later

and put another layer
on top of that,

to make this transition
very soft.

Leonardo's techniques are still
being taught today

in his hometown of Florence.

To make their paintings
come alive,

artists strive to capture
human flesh

and the way light
reveals its shape.

Leonardo speaks

about the smoky transition
of light to shade.

That's how we perceive
in nature.

The problem often
with photographic images we see

is that there's so much detail,

we don't get the broader effect.

We see life very much
out of focus... we glance.

Other artists of the day,

like Sandro Botticelli,

painted figures
with hard outlines.

But Leonardo used
his fine layers

to create soft transitions,
obscuring the lines.

This is his signature look,
called "sfumato,"

from the Italian "fumo,"
or smoke.

the most famous example

of Leonardo's sfumato

is that enigmatic smile
of the "Mona Lisa."

Just look at the mouth.

Look at the eyes.

You can't see lines.

You just see
the movement of the light.

That's incredible,
and there is no comparison

with other artists at that time.

There's no edge there at all.

It's all very uncertain.

This plays a psychological role,
of course,

because she is present
but somehow not tangible.

She is idealized.

For Leonardo, sfumato captured
in two dimensions

what he observed
in the three-dimensional world.

But in order
to get the skin just right,

he had to go deeper...

to the muscles
and tendons below.

Hold it like that.

Trudy Van Houten

has taught anatomy for 30 years.


Leonardo da Vinci constantly
inspires me.

She says the science of anatomy
is beautiful.

Would you like me to cut that?

Yes, please.

Though the process often is not.


You've beautifully preserved

that tiny little vessel.

Leonardo dissected 30 bodies.

And with no refrigeration,

it would have been
especially unpleasant.

The intestines would've been
a particular problem

because they contain
a lot of bacteria.

And even after death,

the intestines become inflated,
and larger and larger.

That's where things
were going to go bad quickest,

and smell the worst.

It's a very messy business.

Many of the drawings

from Leonardo's
messy dissections

today live on
in the most refined of places:

Windsor Castle,

just outside of London.

Steps away from where
Prince Harry and Meghan Markle

posed for their wedding photos,

more than 200 Leonardo drawings
are secured in the Print Room.

Martin Clayton is the curator
of those drawings.

He couldn't help himself

making a beautiful drawing.

But what most interested
Leonardo was the structure,

the machinery of the body.

And this particular drawing
is one of the finest examples

of Leonardo trying to understand
how the shoulder works

purely in mechanical terms.

There's no mystery of the body.

The body is a machine
that can be looked at

and analyzed
in purely objective terms.

The beauty of Leonardo's
drawings is undeniable.

But in light
of all that we've learned

with the help of tools
like the MRI,

did he get it right?

If I were asked to grade
his anatomical drawings,

they would go from A to F.

His drawing of the muscles,

of things that he was
directly observing

and giving functional sense to,

those I would give an A-plus.

In terms of some of the organs,
I could not do so.

One of Leonardo's most ambitious
anatomical drawings

is called the "Great Lady."

It is considered a masterpiece,

but for Van Houten,
it's a bit of a mess.

The feature I went to right away

are strange structures

flying out
from the sides of the uterus.

They reminded me
of carrots with tops.

These strange sort of
horn-like structures

are ligaments
observed by Leonardo in a cow.

Leonardo assumed

that all mammals
have the same structures.

He's sort of feeling his way
into a field

that had never
been illustrated before.

Leonardo's ground-breaking

certainly informed his art.

He returned to this painting,
"Saint Jerome," after 20 years,

revising the neck to accurately
portray the muscle beneath.

He did not revisit
one of his earliest paintings,

"Ginevra de' Benci,"

and it shows

in what has been called
the flatness of her face.

But by the time
of the "Mona Lisa,"

Leonardo's knowledge of anatomy
is beautifully convincing.

One intriguing page
of Leonardo's notebooks

shows several illustrations
of human lips

in exaggerated expressions,

done from dissections.

And it shows how each muscle
and each nerve affects the lips,

and at the very top
is this tiny faint sketch,

and you see the first sketch

of what will be the smile
of the "Mona Lisa."

Anatomy and his painting

explain in part how Leonardo
infused the "Mona Lisa"

with a lifelike quality.

But to complete the illusion,

he needed to explore
another area of science:

how humans see.

Among the many aspects
in which Leonardo

was using his knowledge
as a scientist

to become a better painter

is optics.

And optics is called by Leonardo

"perspectiva"... perspective.

It's basic geometry,

because when you have an object
with parallel lines,

they will seem to vanish
into a point,

which is called
the vanishing point.

Leonardo was fascinated

by many aspects
of how we perceive our world.

He even studied
the composition of air

to determine
how atmosphere affects

the appearance of objects
in the distance.

Leonardo is trying to capture
the complexity of the world.

But how can you paint something
that you cannot see,

like the transparency of air?

Leonardo not only looked
at mathematical perspective,

but he looked at how colors
change as you get further away,

how the sharpness of something

as you get further away from it.

And did Leonardo also discover
tricks of perception

to pull off the greatest
illusion of all:

that elusive smile?

She's looking out,
and her smile is a reaction

triggered by the arrival
of somebody.

This is the fiction that
the painting tries to establish.

The great artists know
how to draw you in,

but not to tell you
what to think.

They offer the tease.

The ambiguity
of Mona Lisa's smile

is indeed part of her allure.

How did Leonardo
pull that effect off?

That is a question
that intrigued

Margaret Livingstone.

She studies
the human visual system:

how our eyes and brain
operate together

to make sense of the world.

As a neurophysiologist,

I actually learn a lot
from artists,

because they study how we see.

I study how we see.

A lot of good art
takes advantage

of the computations
your brain makes

by exaggerating things

that your visual system
finds important.

Human vision is among the best
in the animal kingdom.

The center of our retina

is packed
with special photoreceptors

that enable us to see details,
or sharpness.

But away from the center...
toward the periphery...

there are fewer of those types
of receptors.

We can see movement,
but not detail.

Okay, now I want you
to close your eyes.

I'm going to put up
two version of the "Mona Lisa,"

one accurate and one distorted.

To illustrate,

Livingstone enlists
her colleague Peter

to see if he can spot
a fake "Mona Lisa"

using just
his peripheral vision.

Okay, briefly open your eyes

and look at the yellow spot,

then close them right away.

And point to which is
the accurate reproduction.

Open your eyes and see

whether you chose
the correct one.

Point at the real version.

Can I keep that?

Peter got only one of four
"Mona Lisas" right,

and Livingstone says
that's not unusual.

Most people don't know how bad
peripheral vision is,

because as soon
as something happens

in their peripheral vision,

they look at it,

and then they bring
the high-resolution part

of their visual system onto it.

In fact, our eyes are
constantly moving...

three times a second,
filling in the details.

The effect got
Livingstone thinking:

could this explain

why the "Mona Lisa" sometimes
seems to be smiling,

and sometimes not?

Using a photo app,

she blurs the image,
like in our peripheral vision.

So I filtered the image

in such a way that it would look

like what you would see
to your peripheral vision,

knowing what I know
about processing.

The result?

She's grinning from ear to ear.

As you look at the "Mona Lisa,"

your eye moves
around the painting.

When you look away
from her mouth,

it enters
your peripheral vision,

and Mona Lisa appears to smile.

But look directly at the mouth,
and the smile vanishes.

She seems like she's alive,

because she looks different

on where you're looking.

Leonardo's paintings come alive

because he understands
human emotion,

and because he has a good feel
for the underlying science.

That combination comes together

year after year as he's doing
the "Mona Lisa"

to make it
such an interactive painting.

Back at the Louvre,

Cinzia Pasquali has removed

the old yellowed varnish
from "Bacchus,"

the brilliant original colors.

It reveals
an atmospheric perspective

that suggests Leonardo's touch.

Taking off these layers of
darkened and yellowed varnish,

we were able to rediscover
the original forms,

the quality of the blue.

It's a wonderful blue.

And see how the painter
represent these cities

with that effect of humidity,

of what Leonardo called
the atmospheric perspective.

But Pasquali's investigation

has also uncovered details

like the harsh shading
in the face,

that don't show

the characteristic
sfumato fingerprint of Leonardo.

I can't see Leonardo's touch.

This is a little mechanical.

This line for the shadow
is so hard, you know.

Leonardo don't do this.

Pasquali and the team
at the Louvre

have solved
a centuries-old mystery.

The "Bacchus" cannot
be attributed to Leonardo.

But that doesn't mean
he wasn't involved.

Very often, his apprentices are
actually painting the pictures,

so he would conceive
the general design of the work,

and then the manual execution

would be delegated
to members of his workshop.

The restoration has succeeded

in bringing much of the original
beauty back to this painting.

But it also raises
an intriguing question:

should the same thing
be done to the "Mona Lisa"?

You have to imagine
that under that varnish,

you could see
a wonderful blue sky.

Probably also the face
or the hand are more pink,

like natural skin.

If we could just take
that varnish off,

we could see it
the way Leonardo really did it.

But I think French governments
have fallen for less cause

than trying to take the "Mona
Lisa" out of circulation

and clean it.

Perhaps there is another way.

Could she be given
a digital makeover?

That is what Pascal Cotte
is trying to do.

He has analyzed the "Mona Lisa"

with a remarkably powerful
camera and lights,

which he demonstrates
using a replica.

We make the measurements

in the basement of the Louvre,
inside the laboratory.

It's very emotional,

to have the painting
in your hands

without the frame.

You can look at this painting

under this very intense light,

that reveal everything
that you cannot see usually.

Cotte's extremely detailed scan
of the "Mona Lisa"

and his analysis of the optics
and chemistry of paint

reveal how the colors
may have changed over time.

It's not just the varnish
that yellows and darkens,

but the pigments and oil
in the paint itself.

Cotte's challenge
is to reverse-engineer

the effects of that aging.

This is not just
photoshopping it

and messing around
with the colors,

which you and I could do
and get tolerable results,

but this is based
on pigment analysis.

First, Cotte determines how much
the varnish has darkened,

and with his computer,
peels it away.

Next, he identifies
what the color of each pigment

would have looked like
500 years ago,

and recreates them to see
the colors just as Leonardo did.

For example, we know
that Leonardo make the sky

with white lead
and lapis lazuli.

So, we have software

that remove the wrong colors

to obtain the genuine color.

Then, pixel by pixel,

Cotte restores those colors.

Suddenly, a greenish sky
becomes brilliantly blue,

and a bit of flush
comes back to Lisa's cheeks.

Finally, as the French say:


Suddenly, she doesn't look
like a submarine goddess.

She looks
as if she's in the fresh air,

which is just terrific.

Cotte's restoration
has brought Lisa back to life,

at least digitally...

closer to the state
that Leonardo saw her,

allowing us all to see
the painting's legendary beauty

and the science it took:

the geometry
and optics of perspective;

the anatomy behind her face;

and the sfumato soft lines,

capturing the mystery
and movement of life.

But even with
all the modern insights,

the "Mona Lisa" is vastly more

than the sum
of her scientific parts.

Pinning down exactly
why we are so drawn to her

remains as elusive as her smile.

Three years before his death,

Leonardo was invited to France

to live and work for the king.

He crossed the Alps
by horse or mule,

carrying three paintings.

Those paintings,
including the "Mona Lisa,"

now hang at the Louvre,

where the doors
are about to open

on the 500-year blockbuster
Leonardo exhibition...

a celebration of a genius
who fused together

the worlds of art and science.

Leonardo is an Italian
Renaissance painter,

but his genius is universal,
and it speaks to everybody.

Leonardo wanted you to forget

that you're looking
at pigments on a piece of wood.

The idea is

that you're looking at a real
living, breathing being.

The key to Leonardo da Vinci

is that he doesn't make
a distinction

between the beauty of nature
that he studies in his science

and the beauty of his art.

He could have spent more time
just being a painter.

But had he done that,

he wouldn't have been
Leonardo da Vinci,

and he wouldn't have
painted the "Mona Lisa."

To order this "NOVA" program
on DVD,

visit ShopPBS
or call 1-800-PLAY-PBS.

This program is also available
on Amazon Prime Video.