Michelangelo's fresco painting technique demonstration from a NOVA episode.

Michelangelo's fresco painting technique demonstration from a NOVA episode.

- [Narrator] It's known
that his basic approach

was a standard technique
called buon fresco,

which is still taught at places

like this international
conversation organization in Rome.

The chief conservator
is Paul Schwartzbaum,

now with the Guggenheim Museum.

He explains what has been
learned from the restoration

about Michelangelo's technique.

- We're going to try and make
a reproduction, if you will,

to recreate the working
technique of Michelangelo,

the way he painted the frescoes
of the Sistine ceiling.

We're going to use the same materials

and we're going to try as best we can to,

we're not Michelangelo, but to recreate

his working technique.

The materials
(metal scraping)

that you see on the floor,

we know from analysis,

these are the materials
that Michelangelo used

to make his plaster.

(water splashing)

- [Narrator] The plaster
is made from lime,

water, and a brown volcanic
ash called pozzolana.

These are mixed into a
smooth violet-colored paste.

(scraping loudly)

The plaster is applied to a surface

prepared the day before
called the arriccio.

This fresh, wet layer, the intonaco,

is applied just before painting.

(scraping loudly)

- The word fresco in Italian means fresh.

And what it means is that we're painting

on the fresh plaster.

The painter was obliged

to work before the plaster dried.

Now, this means that the plaster

could only be applied little by little

as the painter worked,

in terms of what he thought
he might finish in a day

or before lunch, or what have you.

There's a word in Italian

which is called the (in foreign language).

We know from cleaning of the Sistine

that colors are very bright

and Michelangelo wanted
these bright colors.

To do that, we see that in certain areas

he put on, at the very end,
just before he painted,

a very bright white, more light let's say,

very, very, very thin
layer of preparation.

But very rich in lime.

Very thin, it'd be a
millimeter or two thick,

what he's putting on now.

Like a sheet of paper.

- [Narrator] After the plaster is applied,

the design is transferred using cartoons,

drawings on paper.

The contours of the figure are
incised into the wet plaster,

sometimes using a piece of wood.

A different technique is used

to outline the details around the face.

- The other technique is
called spolvero in Italian,

and probably called a
pouncing technique in English.

We make a series of small
holes along the lines

in certain very key points.

Michelangelo, we see,
did the eyes, the nose,

the mouth, the ears, the throat.

And then, takes a little sack of charcoal

or some powdered pigment

and then, you'll see the
pigment goes through the holes

and leaves the design on the fresco

so he has something to use
as a guide for painting.

(slapping loudly)

Okay, let's take it off.

(paper rustling loudly)

You see, that would be

how Michelangelo transferred his design.

With that, it gives you
a base for painting.

- [Narrator] Michelangelo mixed
ground pigments with water.

He used just seven colors
derived from minerals

found in earthen clays.

For his greens, he used green earth.

Ochers for his yellows and reds.

And cobalt or lapis lazuli for the blues.

When Michelangelo applied
the colors to the wall

they had a translucent
quality, like water color.

But as the plaster dried,

a process called carbonation took place.

Carbon dioxide in the air

combined with the lime in the plaster

to form a hardened rock-like
surface of calcium carbonate.

As a result of this process,

the pigment particles
were cemented in place,

becoming a part of the wall.

- A standard fresco technique
is a rather stable technique.

When it's done well, it
lasts thousands of years.

We have Roman frescoes that
are close to 2,000 years old.

- [Narrator] But did Michelangelo

vary the standard technique in any way?

Embellish it, perhaps, by
adding any other layers of paint

or glue varnish to the
surface of the fresco?

Unfortunately, there is no complete record

of Michelangelo's working technique.

In letters to his family,

he did write about painting the chapel.

But he mostly complained

of the uncomfortable working conditions.

"In front, my skin grows loose and long.

"My head is bent back on my shoulders.

"And my paintbrush drips a
rich mosaic onto my face."