Have you ever been out to a store and you
come across a famous painting, or at least something
that you think might be made by a famous artist?
But you're not sure, I mean, due to the price,
and you would like to know, is it like a forgery?
You know what?
There's a process behind that and it involves
some really crazy science.
You've got to check this out.
Follow me.
This episode is funded by The Glick Fund and the Christel
DeHaan Family Foundation, who inspire
philanthropy and creativity.
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All right.
So we're down here in the basement,
which is actually a fascinating part of your museum,
by the way.
So is this the piece that you were discussing, that we're
going to kind of overview?
This is the painting.
This is the painting that we suspect is a forgery.
So tell me about that, the artist.
Well, so the artist that we think
is responsible for this piece is Icilio Federico Joni.
And he has sort of a fascinating life history as well.
He actually was sort of classically trained
in all the proper techniques, so he
was capable of completely making one of these paintings
from scratch like you would have in the middle ages.
We usually begin with just a close visual examination
of the artwork.
So just to describe what we're looking at,
again, this is a medieval painting or supposedly
a medieval painting.
We would expect that the paint is
going to be egg tempera from this time period.
So it's pigment mixed into egg yoke.
It's on a wooden panel, so this is a panel painting.
It's a relatively large wooden panel.
You can see the thickness.
NATE HECK: Yeah, it's really thick.
So we're looking at relatively low magnification.
And so what you see here is the ground
layer, that white material, would
have been the original layer that's
placed onto the wooden panel.
The red layer that you see in there is material called bole.
It's kind of the glue that will cause the gold to stick.
And then as it is aged or artificially aged,
all of these layers begin to break apart
and the cracks form.
So you can see several of them here in this detail image.
And then inside of those cracks, you'll
notice they're quite dark.
Yeah, really dark.
And so that is, under a natural condition,
just an accumulation of dirt, and grime, and old varnish.
A forger might want to enhance these cracks to make them
really pop by pushing something into those crevices, perhaps
a pigment or a dark resin material.
So what you're looking at here is just a diffused reflection
image and using visible light-- what
you saw when we were looking at it on the table.
But then if you move that light source to the far extreme,
it will begin to cast shadows.
And it gives you an idea of all the surface deformations
that exist in this painting.
You had mentioned earlier that it's a highly textured piece.
And so you really begin to pick out
some of that texture, examples of the cracks
that are running through the surface, the craquelure that
is in the paint.
Now what you're looking at is a fluorescence image.
So we've shined a black light onto the surface.
And that ultraviolet radiation is
going to be absorbed by the varnish and the paint
materials.
And then it's going to be re-emitted in the visible.
And that's what we're looking at here.
And it really helps us to pick out some things
about the condition of the piece.
For instance, you can note certain areas
that show up different, where under visible light
they look the same.
This tells us this is a modern intervention, where someone
has done some retouching perhaps of a damaged
area in that gilding.
Now what you're looking at is an x-ray of the painting.
So this is an x-ray just like you would have in the doctor's
office to look at a broken arm.
But instead of looking at bones and flesh,
we're looking at the distribution of the heavy metal
pigments in the artist paints, as well as the density
differences in the wood.
And you can see examples of metal
that have been driven into the wooden panel.
Here for instance is a modern-looking nail
that's going right up through the bottom of the panel.
Other nails here are being used to attach this component
of the frame around the top.
And then you can see those two wooden dowels
that were protruding in the breaking light image.
You can actually see that they've been filled in
or they have a different density from the surrounding wood.
An interesting thing that we noted here
is the little tail end of a screw buried
in the back of the panel, we assume.
The head has been broken off or is missing.
But you can see the threads of the screw, which of course,
would be a modern intervention.
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So this XRF spectrometer has an x-ray tube
that's going to irradiate a small area of the sample,
about the width of your hair, with x-rays.
The instrument takes about 15 seconds, blowing some helium
across the surface to get rid of all the room
air, which would otherwise absorb
our characteristic x-rays.
We can identify lead, a small amount of calcium,
a big signal from barium.
There is some zinc present, looks
like a little bit of chromium.
And it looks like that pretty much accounts for it.
Thinking this is a green earth, we
would expect to see a certain suite of elements
that show up in that mineral.
So that's green earth.
Oh, wow, OK.
Sort of an olive drab color, a yellowy-brownish green.
But curiously in this area, we're
seeing the element chromium.
And chromium is not a component of green earth.
In fact, chromium might appear in a more modern pigment,
a chrome oxide or viridian green.
And you can also tell the color is slightly different.
Oh, yeah.
And the sort of aqua teal of the viridian green
more closely matches what we're seeing,
especially when we looked at that under the microscope
downstairs.
So this continues to raise our suspicion
that this may not be an ancient material,
but might in fact be a material that was
only available after the 1800s.
And that little layer of paint, what
we like to collect and call a cross-section,
and then we'll pluck that little layered cake sample out,
we mount it in an epoxy block, cut and polish it
so that we can see the full history
of the artwork from the conception
to the finished product at the surface.
We're looking at some images of that tiny flake of paint
that Glennis took from the surface of the artwork.
So if you imagine that the painting is sort of
like a cake or an Earth's crust, then what we're seeing here
is the top layer, like the frosting, and then
that red glaze layer.
And then we have this pink layer.
And then below it, this sort of translucent area is the gesso.
So that would have been in the ground layer.
And then this is a really interesting cross-section
because when I take my hand away, what we're seeing here
is one of those deep cracks that we saw
under the optical microscope.
Right, right, the little dark area.
Yeah.
And so you can see that there's two kind of colors
that are present-- a dark, dark brown black, and then
a lighter brown.
NATE HECK: This is so hard for me to get.
I mean, just-- it looks huge because I'm looking,
like it looks down.
But like you said, this thing is just [INAUDIBLE]..
Yeah, so, so this scale bar is 20 microns.
And that's about a fifth of the width of a human hair.
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GREGORY SMITH: Now, you remember that the blue pigment
in the false color infrared was suggestive of ultramarine.
NATE HECK: Yeah.
So for ultramarine from a 1300's painting,
we would expect the source to be lapis lazuli.
We're essentially going to bounce a laser beam off
of the surface of the pigment particles
and measure it scattering.
And that's going to become a molecular fingerprint
for a particular compound, or in this case a pigment.
And then after doing a library match,
we see that we have an amazingly good match with the reference
spectrum here in pink, and that's for ultramarine.
It really is a very clear--
NATE HECK: Oh, like exact match almost.
Yes.
And so our spectrum is coming from a synthetic version
of just the blue.
NATE HECK: Gotcha.
But we can tell that it's synthetic.
And that's interesting because it
wasn't synthesized until 1826.
Oh, wow.
So.
OK.
That's like a huge red flag.
We've provided some pretty clear evidence--
physical evidence-- that this cannot be 1300's panel
painting.
There's the use of modern pigments
throughout the full extent of the artwork.
And they were just not available to an artist back in the 1300s.
I think we're pretty much convinced that this is not
what it purports to be.
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