The Eiffel Tower and the Trocadero.

The Eiffel Tower and the Trocadero.

These spectacular postcards of France in the last years of the 19th century offer a rare glimpse of French cities in vibrant colors. They were created using the Photochrom process, a technique by which black-and-white photos were imbued with vibrant and lifelike color.

The photochrom process was invented in the 1880s by Hans Jakob Schmid, an employee of the Swiss company Orell Gessner Füssli—a printing firm whose history began in the 16th century. Füssli founded the stock company Photochrom Zürich as the business vehicle for the commercial exploitation of the process. From the mid-1890s the process was licensed by other companies, including the Detroit Photographic Company in the US (making it the basis of their “phostint” process), and the Photochrom Company of London. The photochrom process was most popular in the 1890s, when true color photography was first developed but was still commercially impractical.

In 1898 the US Congress passed the Private Mailing Card Act which let private publishers produce postcards. These could be mailed for one cent each, while the letter rate was two cents. Publishers in the US (and later all over the world) created thousands of photochrom prints, usually of cities or landscapes, and sold them as postcards. In this format, photochrom reproductions became popular.

The Photochrom process began with coating a tablet of lithographic limestone with a light-sensitive emulsion and exposing it to sunlight under a photo negative for several hours. The emulsion would then harden in proportion to the tones of the negative, resulting in a fixed lithographic image on the tablet. Further litho stones would then be prepared for each tint to be used in the final color postcard — a single image could require well over a dozen different stones. Though a time-consuming and delicate endeavor, the Photochrom process resulted in color images with a rare degree of verisimilitude, especially at a time when true color photography was still in its infancy.

East coast at high tide, Mont St. Michel.

East coast at high tide, Mont St. Michel.

Notre Dame de Bon Secours and Joan of Arc's monument, Rouen.

Notre Dame de Bon Secours and Joan of Arc’s monument, Rouen.

Entrance to harbor, St. Malo.

Entrance to harbor, St. Malo.

Thiers.

Thiers.

Capitol Place, Toulouse.

Capitol Place, Toulouse.

Tréport.

Tréport.

Trouville beach.

Trouville beach.

Promenade and Grand Salon, Trouville.

Promenade and Grand Salon, Trouville.

Trouville beach.

Trouville beach.

Cable railway, Marseilles.

Cable railway, Marseilles.

Palace of the Grand Trianon, Versailles.

Palace of the Grand Trianon, Versailles.

The Latone Basin, Versailles.

The Latone Basin, Versailles.

Grand Trianon, chamber of Empress Josephine, Versailles.

Grand Trianon, chamber of Empress Josephine, Versailles.

Grand Trianon, chamber of Queen Victoria, Versailles.

Grand Trianon, chamber of Queen Victoria, Versailles.

Gallery of Mirrors, Versailles.

Gallery of Mirrors, Versailles.

Cauterets, Pyrenees.

Cauterets, Pyrenees.

The Hôpital Spring, Vichy.

The Hôpital Spring, Vichy.

The Malavaux near Vichy.

The Malavaux near Vichy.

The Port Militaire and swing bridge, Brest.

The Port Militaire and swing bridge, Brest.

Caen.

Caen.

The valley of Chamonix from the Aiguille du Floria.

The valley of Chamonix from the Aiguille du Floria.

Chartres.

Chartres.

Dinan.

Dinan.

Dunkirk.

Dunkirk.

The throne room, Fontainebleau Palace.

The throne room, Fontainebleau Palace.

Rue de la Republic, Lyon.

Rue de la Republic, Lyon.

Arena, Nîmes.

Arena, Nîmes.

Grand Street, St. Malo.

Grand Street, St. Malo.

Chateau de Duingt, Annecy.

Chateau de Duingt, Annecy.

The Pantheon and the Rue Soufflot, Paris.

The Pantheon and the Rue Soufflot, Paris.

A gallery in the Louvre, Paris.

A gallery in the Louvre, Paris.

Notre Dame, Paris.

Notre Dame, Paris.

Arc de Triomphe, Paris.

Arc de Triomphe, Paris.

The Pavilions of the Nations, Exposition Universal, Paris.

The Pavilions of the Nations, Exposition Universal, Paris.

The Palace Lumineux, Exposition Universal, Paris.

The Palace Lumineux, Exposition Universal, Paris.

La Grande Roue, Paris.

La Grande Roue, Paris.

Eiffel Tower, Paris.

Eiffel Tower, Paris.

(Photo credit: Library of Congress).