Painting and photography have always endured a stormy marriage. But — as a fascinating, sumptuous exhibition of one of art history’s most intriguing curios, the cliché-verre, or glass print, at Peter Freeman Gallery reminds us — the odd couple enjoyed an idyllic honeymoon.

Photography was regarded as both “the handmaiden of science” and an aspiring artistic medium. It also proved an irresistible source for painters in search of ultimate truths in nature. But as much as its early exponents aspired to painterly effects, the new technology soon encountered antagonism from artists already battling the soulless mechanical effects of the Industrial Revolution. Photography was “art’s mortal enemy,” according to critic-poet Charles Baudelaire; “photographs are admirable, but one must not admire them,” declared Jean-Auguste-Dominique Ingres.

But these rumblings were from between 1859 and 1862, when the status of photography was becoming a matter of legal controversy as the medium was incorporated into copyright law. Earlier in that decade, a happy, carefree moment of exchange between the most advanced painters of the day and reproductive technology was focused, as befits a honeymoon, on one of France’s most picturesque locales: the Forest of Fontainebleau. This mythic wilderness just south of Paris was the rustic bohemia favored by Jean-Baptiste-Camille Corot and his circle of Barbizon painters, who were introduced to photography and its expressive, experimental possibilities by pioneers of camera work Adalbert Cuvelier and his son, Eugène. Fontainebleau dominates the imagery of this show, with peasants and horsemen wandering through glades. The medium was highly sensitive to minute marks and thus suited to the depiction of dense foliage.

Corot and Charles-François Daubigny contribute the lion’s share of the 71 prints in Mr. Freeman’s exhibition, which presents, in an elegant salon-style installation, the world’s most comprehensive collection of clichés-verre in private hands. The collection was formed early in the last century by the Parisian dealer and collector Albert Bouasse-Lebel. The other artists represented here are Eugène Delacroix, Jean-François Millet, and Théodore Rousseau.

In a cliché-verre, a glass plate is coated in tallow. Into this emulsion the artist then scratches his design, using an etching needle or the handle-end of a paintbrush, or some other sharp implement. Then, photosensitive paper is placed underneath the glass, which is exposed to sunlight. The light coming through the incised marks darkens the page below, while the parts of the plate still opaque block the light so that the rest of the page remains light. When the paper was photosensitized with salt, the results were called salt prints.

The technique is a hybrid of etching (sans acid) and photography (sans camera). To modern eyes, it is highly curious combination, as the marks are very much handmade, in their scratchy, scribbly immediacy, as in Corot’s “Les arbres dans la montagne” (1856), and yet the printing has all the flattened artifice of a photograph. Clichés-verre thus set off contradictory vibes of intimacy and remoteness.

As a printmaking medium, the great attraction of cliché-verre was its relative lack of fuss: Spontaneity, cheapness, and cleanliness were the hallmarks of its appeal to Barbizon school artists working en plein air, directly from nature and away from fumy ateliers and presses. The way the print captured every nuance of the artist’s touch perfectly matched the Barbizon aesthetic’s mix of ethereal, idealized romance of landscape and its sense of capturing fleeting impressions literally as they occur.

Unlike an etching, say, where the worked side of the plate is pressed against the paper, in a cliché-verre the light can pass through either side of the glass plate. Thus, sometimes the image is the same way around that the artist worked it on the glass; other times it is reversed. In many instances, the Bouasse-Lebel collection at Freeman includes different impressions of the same image, printed both ways, showing how the artist modified the image between exposures — another appealing aspect of cliché-verre for romantic artists committed to working uninhibitedly. Versions of Daubigny’s “Le Marias aux canards” (1858–62), for instance, show experiments with different tonalities, between brown and black inks, with the boat at the top of the composition receding or asserting itself to different degrees.

It is curious that Delacroix should have tried his hand at cliché-verre, as he was on the side that viewed daguerreotypes as a danger to art. In 1853 he had organized an experiment, in his studio, in which guests were to compare nude photographs by Eugène Durieu and old master engravings of similar subjects. As he wrote in his famous journal, “This machine-art spoils the masterpieces.” His objection to the literalism of photography, however, arises from the camera’s impassive recording of nature, rather than the means by which the photograph is printed, which is the part of photography exploited by the cliché-verre. His “Tigre en arrêt” (1854) exposed both ways in two prints — an early proof and a more worked image — shows the big cat surprised, as if by the image’s maker or beholder, which creates a visceral sense of immediacy.

Despite such eminent experimenters as Delacroix, Corot, and Millet, the cliché-verre died an early death as a medium. In a way, it fell between the stools of innovation and tradition. While photography would soon revolutionize commercial printing with photogravure, fine artists looking to make prints turned to the time-honored techniques, such as etching, precisely for the physicality, the sense of facture, that a sensitively etched plate could yield. For Corot, indeed, cliché-verre was an entry-level medium that led him to overcome his initial resistance to the old-fashioned technique of etching and its demands.

Until January 19 (560 Broadway, #602/603, at Prince Street, 212-966-5154).