I work with computers and digital video a lot,
which means that I think of colorin terms of light,
in terms of amountsof red, green and blue.
Someone who works with printmight think of color
油墨的结合 如青色 品红色 黄色和黑色
in terms of combining inks,cyan, magenta, yellow and black.
A physicist might think interms of the frequencies
and wavelengths of the light,
but there is a very different way to look at it,
through the chemistry and compoundsthat make up colors.
Inside those buildings,the Harvard Art Museums,
is the Forbes Pigment Collection.
– The pigment collection was put together
by Edward Forbes, who wasthe second director of the museum.
He had been buying works of art and
in doing so he discovered that the dealers in Italy
were seeing American collectorsas something of a mark.
What he decided is that if you understand what a work of art is made of,
what the original materials werethat an artist used,
then you can tell original from restoration,original from fake.
And so what he did wasstart buying pigments
to use as standards for theanalysis of works of art.
Knowing that it was visible to the public meant
that I needed to make some sense
of what we have as a collection.
So what I did was take a color wheel,
open it out, have yellow in the centre
and we go along one way to blue,
along the other way to red,
and purple at each end.
So we have unique colorsalong the top,
we have duplicates of those colors,
which are chemical duplicates,but not actual color duplicates
and then underneath on thebottom shelf we have
the raw material thatmakes up the colors above.
In effect, what we have are the materials that make up paint next to each other
and then if people lookat the galleries below,
they can actually see what artists can do with these raw materials.
如果你想一下 比如说 氧化铁 赤铁矿
If you think about iron oxide for example, hematite,
but as it forms in the earth,
those slight additions that the earth addsinto the hematite deposits
allow it to look slightly different,
so we have 60 differentsamples of hematite.
Each of those is a slightly differentshade from the other.
These pigments are notused for restoration.
We use them only as standards for analyzing samples from works of art.
By analyzing the materials,we can understand
the thinking process and if the artistis no longer alive,
it’s really the closest way to having an interview with the artist.
It’s also great for teaching.
We can show the studentshow pigments change.
They not just fade, butsome pigments darken.
It’s like Vaseline, but 80 years old.
It doesn’t last forever.
Vermilion red lead will turn blackon exposure to light.
You can see how it started.
And then other pigments like eosin, which Van Gogh used a lot,
will fade and give anentirely different impression
of what the painting was to whatit looks like now.
And so for security, we don’thave the public in here.
Some of the pigments are toxic, so we don’t want people touching them, playing with them.
So pigments are made of mercury, they’re made of cadmium,
arsenic and so on.
The oldest white pigment is lead white.
It’s made by taking lead metal, putting it into a container with vinegar.
That container is buried in cow dung,
so out of manure you get the most pure beautiful white pigment.
That’s been around forhundreds and hundreds of years.
People used it as makeup.
Lead white is toxic in theway that lead is toxic.
We have mummy brown.
It has been used probablysince the 17th century
and it’s made up of Egyptian mummies that have been ground up into pigment.
Indian yellow is an interesting pigment.
It’s made by feeding cows mango leaves only
and collecting the urineand drying the urine.
What you see on the screendepends on the limitations
of what the computer screen can depict.
So videoing them,putting them into the digital format,
doesn’t replicate the color.
There is innovation and people are developing new ways to depict colors.
So for example, Mas Subramanian developed a blue pigment called YInMn Blue.
He discovered it by accident.
It’s very stable and it’s the
first inorganic blue pigment that’s been invented for a couple of hundred years.
There’s been a new black that’s come onto the market,
which is Vantablack, which stands for Vertically Arranged Nano-Tube Arrays.
What you have is a forest of very tiny tubes and light will go into that.
It will bounce around inside the tubes and then get issued as heat.
It’s a beautiful velvety looking surface that doesn’t bounce any light back.
Chemists produce more andmore pigments every year
and I think that we’re going to seepigments depicting colors
that we never thought were possible.
Every day somebody is coming in here,
taking a pigment out and using itas a reference.
This was beautifullyarranged when I installed it.
It took me like four monthsof lining everything up
and it’s all a littlehiggledy-piggledy now,
so you can tell thatwe use it all the time.
It’s not an historic artifact,
it’s something that we relyon to do our work properly.
– My thanks to everyone atthe Harvard Art Museums.
Pull down the description for more about them and more about the pigment collection.