Think you know your colors? Red, orange, yellow, Yves Klein blue, even VantaBlack, perhaps? But how about Stuart Semple’s Pinkest Pink? Or the lost, forgotten, and rediscovered 17th century lead-tin-antimony yellow? These are just a couple of examples from thousands of rare color pigments Narayan Khandekar works with in his role as Director of the Straus Center at Harvard Art Museums.

When Narayan isn’t digging up golden ochre from Australia’s Arnhem Land coast, he can be found here at Harvard researching and better understanding the materials and techniques used by artists through the ages. Likening his practise to that of forensic science, but instead of a crime scene there is a rare work of art. In essence, Narayan wants to discover not just when a painting was created but to decipher exactly what it was made of and how it was done.

We caught up with Narayan in his fourth floor laboratory to discuss conservation, preserving Rothko murals, and future-proofing fine paintings.

Tell us about your work lab: Does it really house over 2,500 different color pigments?

The Straus Center labs are situated on the fourth and fifth floors of the Harvard Art Museums, with glass walls that overlook the interior courtyard and allow the public to see in. The pigments are stored in glass-fronted cabinets and on the fourth floor is my lab (the analytical lab). Yes, we do have over 2,500 pigment samples. We also have a large collection of binding media, varnishes, and resins that are also displayed in the cabinets.

Many one-of-a-kind pigments each tell their own unique story. Do you have any favorite stories you’d care to share?

I like the story of lead tin yellow. It was the predominant yellow up until about 1750. It disappeared from use, possibly replaced by Naples yellow. It was rediscovered in 1940 by researchers at the Doerner Institut in Germany. Another pigment used in the 17th century by Orazio Gentileschi was lead-tin-antimony yellow (see The Lute Player in the NGA), which was rediscovered by my colleagues Ashok Roy and Barbara Berrie in 1998. The reason I like these stories so much is that they tell us that pigments are used and forgotten about all the time, which means there are lots of discoveries yet to be made.

How do you use match color pigments to works of art? And is this one way in which a piece can be deemed authentic?

A painting starts changing as soon as it is finished. The colors change, the medium cracks, and so on. When we restore a painting, we are matching the current condition of the original paint. Also, any restoration work we do has to be reversible, and is separated from the original by a layer of varnish. We do not have to use the same pigments as the original painting, but simply match the color, so that you can enjoy the painting without being distracted by damages.

From your experience with fine paintings, did artists take huge risks with toxic pigments in order to pursue their chosen hues?

Very much so. Lead white is one of the most ubiquitous pigments, and we all know how harmful lead is. Artists have used pigment with lead (red lead, lead white, minium), mercury (vermilion, cinnabar), arsenic (emerald green, orpiment, realgar), cadmium (cadmium yellow, cadmium red, etc), cobalt (as a drier, Cobalt blue), and the list goes on. Every time an artist licked the tip of their brush to get a good point, they were taking a risk.

Can you tell us about some of the rarest pigments? And can these ever be recreated synthetically?

One rare pigment is Mummy, which requires an Egyptian mummy. It would be difficult to make synthetically as it uses asphaltum, which is itself a complex material of geological age. It has not been produced for around a hundred years. Another rare pigment is ultramarine, which was ground from lapis lazuli and was as expensive as gold and had to be mined in Afghanistan. However, in 1826, a synthetic version was manufactured, which changed the value of the color.

In layman’s terms, can you explain how you use science to understand and study great works of art?

We use scientific instruments to identify the materials an artist uses. For example, we use infrared and Raman spectroscopy to identify a pigment. We collect a spectrum and compare it to a library of standards, and then match up the peaks. We can use gas chromatography to identify the medium, determine if linseed, walnut or poppy seed was used, and if additives like resins or other oils were added. It’s a lot like forensic work, but we are looking at a work of art, and not a crime scene. We want to understand what a painting is made of, and how it was made.

How is technology (the use of light or computer algorithms, for example) an integral part of the restoration process?

The five panels that make up Mark Rothko’s Harvard Murals had been on display in high light levels in the 1960s and ’70s in a university penthouse dining room. They became faded in an uneven way and the cycle no longer worked as a single unified work as the artist intended. The delicate, unvarnished matte surface of the Rothko murals meant that we could not restore them in the traditional sense by applying paint, as it would be irreversible, and it would cover the artist’s original paint. We decided instead that we could control the light that is shone onto the paintings so that it compensated for the lost colours.

To do this we had to work out what the murals’ colors originally looked like, which involved the University of Basel and the expertise of Prof Dr. Rudolf Gschwind to digitally restore Ektachromes taken of the paintings in 1964. Then we worked with the Camera Culture Group of the MIT Media Lab to write software that would allow us to calculate and project the right colours, pixel by pixel—over 2 million pixels per painting—using InFocus widescreen short throw projectors that were carefully aligned with the paintings. This all required a great deal of programming, and as we were doing this for the first time, a lot of perseverance and support to see the project through. This project was only possible because the technology was in the right place, and the right group of people were all together at the same time, and the Harvard Art Museums had the foresight to invest in this groundbreaking work.




Read the full interview and find more images of Narayan Khandekar and his Harvard lab on Freunde von Freunden.