It can be beetles that come off a cactus,

it can be the dried urine of a cow,

little insects that grow on an oak tree,

a chunk of lead that's soaked in vinegar.

It's truly amazing.

(cheerful music)

We're in Harvard University,

outside the Forbes pigment collection.

Pigment is a very small particle of colored material

that is mixed in with a binding medium.

The pigment gives paint its color.

(Bright music)

The Forbes pigment collection has been brought together over several decades.

We have around 2,500 pigments.

We have a lot of very unusual and very rare colors.

So this is, I think, one of the more unusually named pigments.

It's called dragon's blood.

It doesn't come from dragons, it comes from rattan palms.

And it give a very bright red pigment.

The unusual aspect of mummy has to do

with its source rather than the color itself,

and that comes from Egyptian mummies.

And it's the resin that's applied to the outside of the bandages.

I think the rarest color that we have

is actually an entire ball of Indian yellow.

And this is a pigment that is made from the dried urine of cows

that are fed only on mango leaves.

If you're looking at a work of art,

and you want to understand what is original

and what's a restoration, you will take

a tiny sample of pigment and analyze it.

A lot of the pigments are actually toxic,

so you don't want to handle the pigments

and then go out to lunch.

There's a green called emerald green

that has an arsenic center to it.

We can use them for telling if something is real or not.

People will say this is by a certain artist,

and we can look at the materials that are used

and decide if those materials were available

during that artist's lifetime.

If not, then we have to look at

who might have painted that picture.

I can't pick a personal favorite.

There's, it's like asking to pick a favorite child.

No, the other 2,400 would feel left out.

(laughing)

(relaxing music)