My wife is on the board of directors of Artek, an early music ensemble. The instruments the group plays include the harpsichord, fortepiano, viola da gamba, cello, violin, cornetto, recorder, dulcian, sackbut, lute, baroque guitar, and theorbo. Many of these are beautiful-looking instruments, but most sound a bit odd, slightly off the pitches we are accustomed to. Nonetheless, in the hands of skilled musicians their capacity to produce work of great beauty has not been exhausted: It may be inexhaustible. More modern musical instruments display new capabilities, but older ones do not lose their capabilities when they are superseded; their potential just goes unrealized. The same is true of photographic technologies overtaken by progress.

“Young America: The Daguerreotypes of Southworth & Hawes,” an exhibition organized by the International Center of Photography and George Eastman House, features more than 150 daguerreotypes by two of the great 19th-century American practitioners. Albert Sands Southworth (1811-94) and Josiah Johnson Hawes (1801-1901) began working together at their studio at 5 1/2 Tremont Row in Boston in 1843 and continued there for 20 years, although Southworth went to try his luck in the California Gold Rush from 1849 to 1851. When Southworth left the studio partnership in 1863 to produce photographic evidence for law cases, Hawes kept on alone until his death.

What distinguishes the work of Southworth and Hawes is not just that they continued as daguerreotypists long after that practice had commonly been replaced by newer photographic technologies, but that they systematically explored the resources of their medium, producing in the process a magnificent record of Boston’s leading citizens, many of whom were also important actors in the country’s emerging political, cultural, and commercial life.

The daguerreotype has several assets. If the daguerreotypist uses materials of high quality and takes the time to prepare them carefully, the finished picture will have remarkably fine details. The illusion of depth is more pronounced in a daguerreotype than in images produced on paper, and can still astonish first-time viewers. It can reproduce delicate gradations of tone. And the daguerreotype image is more permanent than many others.

The chief liabilities of the daguerreotype are that each image is unique; it cannot be easily copied like those from a negative, and done right it is expensive. Given their upscale clientele and their self-conscious promotion of themselves as practitioners in the fine-arts tradition, Southworth and Hawes worked successfully with in the confines of these liabilities although, in fact, they never made any money. The low-end, high-volume daguerreotypists were the ones who made money. By 1853 there were 10,000 daguerreotype studios in the United States that produced between 3 million and 4 million daguerreotypes for a population of 7 million or 8 million.

Grant Romer, one of the curators of the exhibition and a leading authority on daguerreotypes, gave a talk at ICP in which he began by showing some of the generic daguerreotypes from run-of-the-mill studios. The subjects were placed in uniform poses, were flatly lit, and the duo’s expressions tended to be blank. These images may have a naive charm, like primitive art in general, but they are rarely arresting. The Southworth and Hawes pictures, by contrast, are almost all different from one another. Indeed, their standard procedure was to take four pictures of each subject – varying the pose, the lighting, the props, and the camera position – and let the customer take the one he thought best. The results are not just varied; they are studies in depth of unique individuals, and they impress us with their sense of the subject’s character, social authority, and, in the case of women, beauty, and of children, charm.

The subject of William Hague’s 1880 biography, “Christian Greatness in the Minister: A Discourse on the Life and Character of Rollin Heber Neale, D.D., Forty Years Pastor of the First Baptist Church,” sat for Southworth and Hawes in 1850. He is shown from the waist up, but it is clear he is a man who stands erect. The simple white stock around his neck, his plain satin vest, his coat with its velvet collar and piping, are elegant without being at all foppish. He has manly features, full but regular, so that what most catches our attention is his gaze and his hair. His hair is a piled tangle that appears to be graying, and whether it is simply unattended or an an affectation, it frames his face dramatically. His look is intelligent, shows moral concern, and is earnest in a tempered way: It is emblematic of what was finest in Boston at this time.

How did Southworth and Hawes achieve this image? First of all, they used the finest materials and deliberately polished their plates horizontally so that the light they would be viewed by – from windows and table lamps – would bring out the maximum detail. (The lighting at ICP comes from overhead, but is offset to replicate the original sources.) Their studio on Tremont was on the top floor and featured an enormous skylight whose effects they carefully controlled. Here they probably had it covered with translucent fabric that diffused the light, providing a soft overall illumination, while still being directional enough for shadows to model the subject’s face and give texture to his clothes. We see the sheen on his satin vest, and although his eye wells are shaded, they are not so dark as to obscure the whites of his eyes, the points of light on the pupils, or the pouches underneath them. It is the combination of the lighting and the fine-grained silver that makes the Reverend Neale’s hair such a wonder.

We know from notes Southworth and Hawes left that they continually tinkered with the chemistry of their process, and that they strove in sophisticated ways to improve their art as they imagined great artists of the past had striven. They sought new subjects, shooting outside the studio, and were the first photographers to take bridal pictures with their subjects wearing their wedding gowns: the details of the lace, flounces, textures, and flowers are still a marvel. It is because Hawes kept working as a daguerreotypist long after Southworth left, and because he kept the three of four images his clients did not take, and because his children had enough respect for his dogged career to preserve those images when they closed his studio after his death, that we have such an extensive body of their work. The daguerreotype in the hands of a master is as expressive an instrument as Artek’s viola da gambas.

Until September 4 (1133 Avenue of the Americas, between 43rd and 44th Streets, 212-857-0000).