Tom Learner, conservation scientist

This chemist works to prevent cherished plastic artworks from degrading and disappearing. Interview by Vicky Stein.

April 02, 2018

Tom Learner. Photo: Getty Conservation Institute

Editor's note: Vicky Stein published a news story based on this interview in
National Geographic on May 31, 2018.

Tom Learner approaches his research in art conservation as both an accomplished chemist and a lover of art. But rather than trying to save Renaissance paintings, ancient Greek mosaics and statues, or old textiles, Learner is trying to preserve artworks made of a newer material: plastic.

Plastic water bottles and plastic bags are regarded as cheap, disposable, and nearly indestructible; we don’t treasure most of the plastic that passes through our lives. But synthetic plastics have been appearing in artworks since the invention and popularization of the material in the late 1800s. Learner says that plastic radios, modern paints, and animation cels are worth preserving.

Learner, head of the Science Department at the Getty Conservation Institute in Los Angeles, is trained as both a chemist and a traditional art conservator. He is leading a new project dedicated to the preservation of plastics—for example, animation cells that are part of the Disney Animation Research Library. After his talk at the American Association for the Advancement of Science meeting in Austin, Texas, in February, Learner discussed some of that work with SciCom’s Vicky Stein.

What brought you to this kind of work? It’s a unique intersection of art and chemistry.

I grew up loving science and art, but in England when I grew up, you had to make choices, and the classic ones were sciences or arts.

At the end of my chemistry degree, I had to think about what to do with my life. I had fallen out of love with chemistry, so I went to see a career advisor. For over an hour, this poor guy was desperately giving me things to try to get me excited. But then, he sighed and pulled the very last paper out of the pile and said, "Well, do you like conservation of art?"

I thought that sounded fascinating. I started volunteering at a local museum, and then went to London to train as a painting conservator at the Courtald Institute of Art.

You ended up earning a PhD in analytical chemistry, specializing in studying modern paints. How did that lead to your current project on plastics?

In 2007, I became head of the Contemporary Art Research Initiative at the Getty Conservation Institute for 7-8 years. That’s when my interest in plastics really developed. All the techniques you use for conserving and analyzing paints are used for plastics as well. We’ve developed some analytical techniques, such as how to repair scratches and cracks in plastics, and we’re thinking really long-term about plastic conservation.

So broadly, what is important about conserving art?

I’d like to say, isn’t that obvious? But obviously I can’t.

Not for the purposes of this conversation, not really.

We’re interested in cultural heritage here. That could be an artwork, that could be an architectural feature in a building. If you’re interested in cultural heritage, then conservation is part of the deal. There is nothing known to man or woman that can maintain the same state without changing, for all time. Each generation is the custodian of an artwork for our lifetime. We just make sure we hand off this material to the next generation in as good a state as possible.

Then how does research become important to conserving this material?

Conservation can mean everything from the preventative side, where you look after it well—you don’t let people touch paintings or smear over sculptures—all the way through to how you fix something that has fallen over or become damaged.

And for each of those things, an enormous amount of research is needed. You can find lots of ways to remove dirt from plastic quite effectively, but those cleaning methods might actually start to dissolve the plastic or leach out some of the additives. So every step of conservation requires loads of research to make that treatment more reliable, or safer.

What exactly is in a “plastic?” What makes it interesting from a chemical perspective?

Plastic is a class of materials that can be very different from one another. Most plastics are characterized by a repeating unit of carbon atoms. For example, the simplest plastic, polyethylene, is the ethane molecule joined up with other ethane molecules to form a polymer. There are two types of plastics: thermoplastics and thermosetting plastics.

Thermoplastics can be heated to a “glass transition temperature,” the point at which the plastic goes from glassy or rigid to rubbery. You heat them up and they soften, you cool them and they harden again.

You can use chemicals called plasticizers to bring the transition temperature down slightly to increase flexibility. One example is PVC, which has a very high glass transition temperature. Those rubbery pink plastic erasers are PVC, but they’re very flexible—those are swimming in plasticizers, a huge amount. That’s an extreme case.

There are also all kinds of other additives—things that prolong the shelf life of plastics. In some paint formulations you can have fifteen different additives: surfactants and dispersant agents, antifungal things, freeze-thaw solvents. They can be highly complicated, these plastics.

"Each generation is the custodian of an artwork for our lifetime."

What are some of the objects that you’re working with now?

The Getty Conservation Institute isn’t a typical conservation center—we are the research center, so most of the work is done on materials themselves, not a particular object. But in this particular project we have been working really closely with the Disney Animation Research Library on their collection of animation cels. But this isn’t ten cels we’re trying to restore, it’s the entire collection.

By cels, you mean the transparent celluloid sheets that animators hand-ink and hand-paint characters onto. How do you go about conserving them?

When you talk about animation cels, everyone falls in love with these characters in the paint, but at first, the point for us was the plastic that the cels were painted on. And in fact, it was the dust covers made of the same plastic that were laid over the cels, which often had dates written on them; those were our treasure trove. There were thousands of these things that we could do research on. The Disney library was happy to donate some so that we could do tests.

They’re made of an unstable plastic, inherently—cellulose nitrate early on, and cellulose acetate a bit later. The sheets that we work with at Disney all have a level of plasticizer in them as well.

What does it look like as they degrade?

There are one or two extreme cases where the cels themselves, the deterioration has gone quite far. In some cases they’re starting to disintegrate. In other cels distortions have just appeared. In a few, the plastic has buckled and the paint has detached.

A lot of the cels are in amazing condition. In many ways the Disney people came to us at just the right time.

Why is this the right time?

Plastics are 160 years old now, so even in quite historic collections plastics are appearing. Cellulose nitrate, which is often considered the first plastic, was first developed in the 1860s. But the big explosion of plastics was in the 1930s when a lot of different types began to appear. That was not entirely coincidental to the lead-up to the second World War, which is sadly often what happens. The world started finding huge numbers of uses for these materials.

It was being marketed as a new material, a stable material, all that stuff. I think some of the dramatic degradation wasn’t predicted.

But the early plastics started degrading quite some time ago. Sometimes you think it’s a one-off case, just a few. But the Getty Conservation Institute in 2007 decided it was a big problem. People who collect art and artifacts started to see more objects in their collections start to deteriorate, and that’s when alarm bells started ringing.

What challenges will you face in modern and contemporary conservation, moving forward?

I don’t think there’s a material anywhere, be it natural or synthetic, that isn’t being used for art by someone somewhere. Every plastic, every mineral, every bodily fluid, every paint type, every form of technology, software art, video and computer art, performance, installation art. Sometimes you can’t even define what the material is.

If we apply the same methodology to those materials as we have with traditional materials—oil paint on canvas or panel, marble, bronze, paper, textiles, those five things—if you look at contemporary art it’s an infinite amount of materials. You can’t put the same kind of detail in research… you by definition have to spread yourself thin.

So, we can’t keep up with conservation forever?

There has to be a general acceptance that we will never understand these materials as well as we understand the historical ones, but maybe that’s ok. Some of this art was made for the moment, for impact, for a particular situation. It might become much less relevant twenty years later. With some contemporary art, you start to wonder if preserving the material aspects is doing anything for the art at all.

You cannot keep everything that’s created, but how you decide is a very tough question.

Conservators become decision makers, where we’re weighing all different kinds of criteria. Chances are in 25 years' time someone will look back and say, “What on earth were they thinking?”

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