Ye are the salt of the earth,” says the Book of Matthew. Perhaps that’s why “salt print” photography has a simple and earthy feel. More than one hundred spectacular examples of this early photographic process, on loan from Britain’s Wilson Centre for Photography, are now on view in “Salt and Silver: Early Photography, 1840–1860” at the Yale Center for British Art through September 9.

Within months of each other in 1839, Louis-Jacques-Mandé Daguerre, in France, and William Henry Fox Talbot, in England, announced revolutionary photographic discoveries, setting off something of a nineteenth-century Space Race in the capturing of light and shadow. Each relied on a similar chemical process to “fix” images to a surface. Daguerre’s invention, the daguerreotype, used a metal mirror of photosensitive silver-plated copper. Developed with mercury vapor and fixed with a further bath of chemicals, the result was jewel-like—a small and highly detailed image on a singular, fragile object that was a direct “positive” capture of light.

Talbot’s technology also used silver salt. The difference was his invention of a photosensitive paper that could be stabilized after exposure. By soaking his paper in a salt bath, Talbot found a way to capture and fix light in the paper’s fibers.

Unlike Daguerre’s, Talbot’s process resulted in a negative image; exposure to light darkened the chemistry. This outcome suited his “photogenic drawings,” or what we call photograms today, in which opaque objects are placed directly on sensitized paper and light passing around the obstructions darkens the paper. To make a legible photograph, however, Talbot had to create an extra step. So he took his developed negative (created on translucent paper) and laid it on a second photosensitive page. By exposing light through the negative, he was able to create a second, positive “salt print.”

That extra step, the transferring of negative to positive, made Talbot’s invention (unlike Daguerre’s) a reproducible medium. The ability to create multiple prints from a single negative also made the process more affordable and ultimately helped account for its wide adoption. Evidence of the spread of Talbot’s invention is what is on view now at Yale in an exhibition that originated at Tate Britain in 2015, where it was curated by Hope Kingsley, and is organized here by Chitra Ramalingam and Scott Wilcox.

Unlike later, mass-produced photographic paper, on which photosensitive chemistry is suspended on a glossy surface, salt prints are made by hand on thick, matte paper. What they lose in resolution (compared to daguerreotype) they make up for in feel. With an image captured deep in the paper’s fibers, the salt print photograph most resembled a grisaille drawing, or perhaps an intaglio print.

Talbot called his home, Lacock Abbey, the first building “to have drawn its own picture.”

These connections helped advance salt printing along both artistic and scientific lines. Faced with the technology’s untested possibilities, creative innovation flourished from the very start. A failed draftsman, Talbot spoke both philosophically and spiritually about his invention of captured sunlight and “drawing with shadow.” He called his home, Lacock Abbey, the first building “to have drawn its own picture.”

Due to the limited light sensitivity of his chemistry, Talbot’s early experiments required long exposure times, measured in increments of hours rather than seconds. He also needed sunlight. So landscape was an early focus, such as in The Great Elm at Lacock (1843–45) and the marvelous Nelson’s Column Under Construction, Trafalgar Square (April 1844). So was still life, in which statuary such as Talbot’s Plaster Bust of Patroclus (1843) was photographed in daylight against a black background.

Talbot also understood the scientific implications of his discovery. Through his photogenic process, he created the first photocopies, such as his Fac-simile of an Old Printed Page (ca. 1839). He also used the salt print for inventory, such as in Articles of China and Articles of Glass (1844), proving that even translucent objects could be recorded.

Subsequent salt-print photographers took the technology far and wide. Roger Fenton photographed soldiers in the Crimean War. The studio of Matthew Brady recorded an elevated shot of Landing Supplies on the James River, Virginia (1863–64). Félix Teynard, J. B. Greene, and Maxime Du Camp updated Napoleon’s Description de l’Égypte for the photographic age, while Auguste Salzmann documented the Holy Land.

William Henry Fox Talbot, The photographer’s daughter, Ela Theresa Talbot, 1843–44, Salted paper print from paper negative, Courtesy of the Wilson Centre for Photography.

Because of the long exposure time, especially at first, portraiture proved to be the most challenging, but perhaps the most rewarding, application of the salt print. Talbot’s own image of The photographer’s daughter, Ela Theresa Talbot (1843–44) is endearing. Portraits of figures such as Victor Hugo are amazing to see. The French photographers (unsurprisingly) focused on the nude, with examples here by Julien Vallou de Villeneuve, Louis-Camille d’Olivier, and Nadar.

The Yale Center’s exhibition makes a good attempt at explaining their photographic processes. The curators have written informative labels and published a “Glossary of Photographic Terms,” but I could have used even more. There is one fascinating comparison, by Édouard Baldus, of an identical image produced as both a salt and albumen print, the second using Louis Blanquart-Evrard’s 1850 process that sensitized a layer of salted egg white in a suspension that worked more like today’s glossy photographic paper. While Baldus’s Saint-Valéry (Vue du Port) (1855) gains fidelity in the albumen print, it loses the warmth and depth of salt. The exhibition also features a wax paper negative by Teynard (1851–52) next to his positive salt print, Monument Taillé dans le Roc, Piliers et Sculptures de Gauche (1858).

The unfortunate reality in the digital age is that Talbot’s nineteenth-century invention had much more in common with photography in the twentieth century than does the twentieth with the twenty-first. How can those of the smartphone generation understand any analog photography without time of their own in a darkroom? Like Talbot himself, they may discover it for the first time through these silver prints.