August 1999


Holding back the years

Life Sciences Division researcher develops method to restore fading daguerreotypes

This before-and-after daguerreotype of a nineteenth-century lady called “Liza” illustrates how Life Sciences Division researcher John Miller’s laser process rejuvenates occluded images. The right image clearly shows where work on the image was stopped.
We have no idea, really, what George Washington or Thomas Jefferson looked like except from stylized paintings. But we do have photographic records of John Quincy Adams and Andrew Jackson, of the next generation, primarily because of daguerreotypes—the first successful photographic process.

Like any art, daguerreotypes are subject to the ravages of time. Life Sciences Division researchers John Miller and Valerie Golovlev are developing a way to clean and restore occluded daguerreotypes by using a laser process that cleans impurities and blemishes from the image’s surface.

“There is something magical about the way daguerreotypes look, and much of it may have to do with the surface structure involved in the process,” says Miller, who specializes in photonics, or optical, research. “The pictures are made up of little bumps of silver crystals. They reflect light in a way that suggests depth, and at certain viewing angles you can get either negative and positive images. It’s really a nanostructured image.”

The heyday of Louis Daguerre’s process was from 1840 to 1860. After a century and a half, many photos have deteriorated. Miller says the deterioration is from impurities that tarnish and obscure the image.

“A typical daguerreotype gets a bluish oxidation circle around the edges. It gives it an antique quality, but eventually it can obscure the image,” he says, explaining that the surface deposits can be composed of silver oxide, silver sulfide or even contaminants from a brass mat or cover glass.

Previous restoration attempts with chemical baths can manifest themselves years later in spots called “daguerreian measles.” Miller’s method is to use laser ablation, or laser desorption, to lightly scour the deposits of tarnish from the surface of the image. ORNL’s selection of different types of lasers, ranging from infrared to ultraviolet to pulsed lasers, offered a range of instruments for experiments far beyond any museum’s capabilities.

The resulting process itself doesn’t alter the quality of the image—for instance, the bluish ring, which may be desired, stays behind. But gleaning away the upper layer of haze has clearly enhanced the image in some early experiments with the technique.

“Lasers are used for jobs ranging from welding car bodies to performing eye surgery. They are used by conservators in Europe to clean statues and paintings,” Miller says. “The daguerreotypes present different challenges because, unlike painting and statues, the metallic surface is reflective and the surface scale is of submicron dimensions.”

The idea of cleaning daguerreotypes was met with initial skepticism. “Art conservators, especially, are naturally wary of any process that might alter the appearance of a piece.”

One art figure who likes the idea is Grant Romer, director of museum studies at the George Eastman House in Rochester, N.Y., which has a collection of more than 5,000 daguerreotypes. Another Life Sciences Division employee, Michael Gresalfi, who belongs to a collector’s group, The Daguerreian Society, heard of an Eastman House proposal for cleaning the pictures with lasers and put Romer in contact with Miller.

“I was primed for this because I’d been to a laser conference in Greece, where a collaborator had been involved in laser restorations. The Europeans have used lasers to restore art much more than Americans, probably because they have so much art that’s so much older.”

Romer says the early photographs have a finite shelf life if not properly cared for.

“Daguerreotypes are very vulnerable and durable at the same time,” he says. “That’s true of all photographs. Well protected, they can last a very long time in excellent condition. Not protected, they can be damaged irreversably and destroyed easily. Most of the nineteenth century record has already been lost, similar to early-era motion pictures—only one in 10 are extant.

“Is it important to preserve the first 20 years of printed books? Of course, no matter what condition they are in. You would do what you could to stabilize them and make sure that future generations have access to them. That’s the issue with photography, especially as time goes on. They’ll take on a value that we won’t see today. And we’ll have them if we do the right thing,” Romer says.

Armed with seed money, Miller and Golovlev experimented on some faded images and demonstrated that by honing away the uppermost layer of the daguerreotype, the image can be cleaned.

“We’re not trigger happy,” Miller says. “We want to set a tone of reverence for the art object. We want to develop a technique that is least harmful to the piece.”

That’s important, because similar restorations on statues and paintings have been assailed by some critics as ruinous. To be sure, much of a daguerreotype’s charm is in its blemished antiquity. But a lost image is a loss to the art world and to history as well. Before photography, the likenesses of our forebears could only be guessed at.

Miller, who is working closely with Romer and conservator Paul Messier, hopes to arrive at a commonly used technique for cleaning daguerreotypes.

“Daguerreotypes were a dime a dozen not too many years ago,” he says. “You found them all the time in antique shops. But people started collecting them; they’ve become valued for their aesthetic and historic virtues. Some have sold for hundreds of thousands of dollars.

“Science, really nanoscience, was involved in this process from the beginning; it’s chemistry involving light and silver that created an entire new medium. Edgar Allen Poe wrote about it in 1840, calling it a triumph of modern science.

“I like to regard this work as the nation’s scientists at national labs working to preserve the nation’s heritage,” Miller says.—B.C.


Daguerreotypes: Evermore
France’s greatest gift to America might not have been the Statue of Liberty. It might have been the daguerreotype.

In 1840 Edgar Allen Poe wrote of it: “The instrument I believe must undoubtedly be recognized as the most important, and perhaps the most extraordinary, triumph of modern science.” True to his words, he had his own glum countenance preserved.

“Dags” indeed caused a craze when they arrived on the scene in 1840, especially in America. To this populist nation, portraiture was no longer a realm of the rich. A new medium had been invented, and the daguerrotype’s impact on society is still being felt.

Louis Daguerre improved upon work by a fellow Frenchman, Niépce, who had experimented with fixing light-sensitive chemicals. Daguerre refined the process by treating silver-plated copper sheets with iodine, which made them light-sensitive, and developing the image with warm mercury vapor.

For some reason Daguerre couldn’t market his invention, but an advocate in the French science community wrote so glowingly of the process that the French government granted pensions to Daguerre and Niépce’s surviving son. Daguerre then put the process in the public domain in 1839 as a “gift to the world from France.”

Processes that produced negatives supplanted daguerreotypes by 1860, mainly because they offered unlimited and cheaper paper prints. But it was the daguerrotype that opened the world’s eyes to a new medium and an indispensable technology.