[DIGITAL TONE]
What involves volcanic
ash, dangerous chemicals,
extreme heat, expert
timing, ground pigment,
and expert creativity?
You guessed it, Fresco painting.
Check this out.
[MUSIC PLAYING]
NARRATOR: Support
provided by the Glick
Fund, a CICF fund focused
on inspiring philanthropy.
Additional support provided
by the Christel DeHaan Family
Foundation in honor of
the children and families
of Christel House.
Fresco painting
using wet plaster
dates back to 1500 BC and the
Island of Crete in Greece.
Of course, fresco can be
seen around Ancient Greece
as well, often within
tombs, depicting
scenes of everyday life.
There are even scenes of a
couple dudes just reclining
at a banquet.
However, where we really
see some incredible examples
is in the ancient
city of Pompeii.
In 79 AD, Pompeii was
struck by the eruption
of Mount Vesuvius,
which completely buried
the city in volcanic ash.
To our advantage-- definitely
not to the people of Pompeii--
much of the city was preserved.
Check out these amazing
fresco paintings.
Fresco painting was
definitely the wallpaper
of the day, so to speak.
They included scenes
from everyday life, which
told stories of daily
life, including everything
from being a vendor to a
competition between Pompeii
and a rival town, sort
of a "West Side Story,"
Sharks versus Jets thing.
Apparently, things
got pretty bloody,
which tends to happen when
knives and swords get involved.
Fast forward to the
2nd and 3rd century
AD in Rome, where fresco
painting makes its way
into the wells and vaults of
the underground catacombs,
with biblical scenes
on the limestone walls.
Fast forward even further
to the 13th century, where
we see fresco work exploding.
Of course, once painters
like Raphael and Michelangelo
got a hold of the style,
it was the go-to technique.
Now that you know
the basic history,
let's explore what is
happening within the chemistry,
during the process
of fresco painting.
Let's break down
what we are going
to need to make this
wet plaster mixture.
First is limestone.
Limestone is a very
common rock found
in shallow, calm,
warm, marine waters.
It has a simple
composition consisting
of one calcium atom and one
carbon atom and three oxygen
atoms.
To prepare the
limestone for plaster,
we must calcify the
limestone first,
which means heating
it to 1500 degrees
Fahrenheit or roughly
three times the temperature
your oven at home can reach.
This process of adding
heat breaks down
the calcium carbonate
into calcium oxide
and carbon dioxide.
Releasing all the CO2 in the air
isn't exactly environmentally
friendly.
The calcium oxide we
create from the limestone
is called quicklime.
This quicklime, which
consists of only one calcium
atom and one oxygen atom,
is now a rather toxic powder
of refined limestone.
In fact, this lime
is now an alkali.
An alkali is a basic
ionic salt or earth
metal that dissolves in water.
Since this quicklime does
have a pH greater than 7,
it can cause a chemical
burn on exposed skin.
Keep this in mind as you imagine
Michelangelo and his team
working daily with
this chemical,
60 feet off the ground.
Dangerous?
You better believe it.
Second ingredient
is water or H2O.
What happens next
is fascinating.
When we take lime
and add H2O, the two
react chemically, creating
tremendous amounts of heat.
In fact, tremendous amounts,
as in enough to boil water.
Once you add the calcium
oxide or quicklime to water,
it is now calcium
hydroxide or slate lime.
The third ingredient is sand.
Any idea why they
would add sand?
You would think it would
absorb the water, right?
Not exactly.
Sand, which is basically
microscopic particles
of shells, fish bones, and
rocks won't absorb water.
But the space created
between these particles
can most definitely
hold water and air.
Adding sand created space
within the plaster mixture,
allowing the necessary
carbon dioxide
to creep in and quicken the
creation of calcium carbonate.
But you have to be really
careful how much sand and water
you add to the plaster mix.
At the beginning,
Team Michelangelo
was adding too much water, which
wasn't allowing the plaster
to dry quickly enough.
This caused mold to
form very quickly.
Mold on a painting?
Yeah, that's not so good.
Michelangelo, on the other
hand, had an ingenious idea.
In order to speed up the
drying time of the plaster
and to attain the smoothest
surface to paint on,
Michelangelo added ground
volcanic ash instead of sand.
This idea had been used
within those ancient Roman
catacombs we just talked about.
And guess where he
got this ash from?
Remember Pompeii?
Yep, this volcanic
ash came from Mt.
Vesuvius, the same volcanic
ash that destroyed the city.
As the slaked lime within
the plaster mixture
continues to heat up, it
reacts to the carbon dioxide
in the air.
Here's what amazes me.
As this carbon dioxide
is reintroduced
into the slake lime, the
lime begins to harden
and creates these crystals.
These crystals are calcium
carbonate, or CaCO3.
Does that look familiar?
It should.
It's limestone.
Yep, you guessed it.
We have come full-circle back
to the original molecular
structure we started with.
We're back to limestone.
Before adding paint,
you would typically
need to add two layers of
plaster, called the arriccio.
After the arriccio layer dries,
the final intonaco layer,
or smooth layer, is added.
Of course, Michelangelo and
the other fresco painters
had to paint quickly on
this wet plaster layer
before it turned
back into limestone.
As the paint sinks into the
quickly drying intonaco layer,
the pigment is now being
blended into the calcium
carbonate or limestone.
Now that the pigment is fused
into the limestone layer,
it is very stable and can
survive for centuries.
I don't know about
you, but I had no idea
just how much science was
involved in fresco painting.
Pretty amazing, right?
[MUSIC PLAYING]
On May 10, 1508, work begins.
And man, what a job
Michelangelo has in store.
Let me just short-list
some of the crazy issues
he will have to face.
MAN: Man, that's really high.
One, he has to remove
all the old plaster
within the chapel, which
was going to be a huge mess.
Two, the chapel was not going
to close while Michelangelo
was painting.
So normal scaffolding
covering the chapel floor
wasn't going to work.
Three, it's Rome.
And it can easily get to
90 degrees in the summer,
and that's just standing
outside on the ground.
Four, Michelangelo was
painting in fresco style, which
had very little
experience with and is
one of the most difficult
forms of painting ever.
Five, the height within
the chapel was crazy.
The ceiling was over 60
feet above the ground.
That's over six stories tall.
