Staring into Ironing Board Sam’s smile, beautiful and bright as his fingers dance across a keyboard, one can easily forget that somewhere above him is a man balanced next to a 14-foot-high stand, aiming a large-format camera down at him, waiting for a strobe light to fire.

And that’s just how Timothy Duffy prefers it.

“My goal is to disappear somehow from this experience,” Mr. Duffy said, “so when you see the photo it’s just you and the artist.”

For too long, it was his subjects who were invisible. They are American roots musicians, many of whom were “ignored in their communities for decades,” which prompted Mr. Duffy to step in and help. In 1994, he founded the Music Maker Relief Foundation, which helps them cover basic living expenses as well as promote and develop their careers. By helping them, the foundation has also preserved the work of these musicians, who are the living history of American music’s foundation.

“How do you get these unseen people seen?” Mr. Duffy asked. “How do you get them seen with reverence and how do you get them seen as the great artists that they are?”

Their portraits — done using the tintype process — are at the heart of “Blue,” published by 21st Editions, The Art of the Book. Mr. Duffy said he’s been taking photographs since he was young, but this is his first professional attempt at making art. Still, his primary drive is unchanged.

“I really wanted to focus on myself as an artist and how I could represent these guys and what it really means to me when I meet these people who are completely unknown,” he said.

He taught himself a classic process to document these classic musicians. Shooting digitally, or on film, meant either dozens, if not hundreds, of frames to sort through. But with tintypes, Mr. Duffy gets between three and seven. He also had to teach himself strobe photography, because most of his subjects preferred to show up at night. But lit by a blinding 30,000-watt flash, Mr. Duffy said, some subjects would sit only once and simply declare “that’s enough,” and refuse another shot.

“So you hope you got it,” he chuckled.

In the course of making a single image, there can be long stretches of downtime.

“When I bring my friends in to take their portrait, we’ll work maybe three hours and get maybe four shots,” he said. “So there’s immense concentration on each image, and a lot of study of light and my relationship with the artist.”

Those moments are as important to him as the laborious, and often tricky, process of developing a tintype. What he said people once criticized as the “happy accident” when he was in high school art class has developed into purpose. The temperature of the day, how long the collodion has been sitting before taking a photo, the length of time to develop the image. Even at the final step of varnishing a plate, there is still a chance to affect the outcome, as with the portrait of Dr. Dixon, his harmonica between his fingers. Mr. Duffy had used after-effects to create a moon behind him, but there was also an unintended, ghostly haze around his shoulder, giving the scene a mystical cast.

“At first, you really get kind of worried about it, and then you try to start going with it, hoping something beautiful comes out in that process,” he said. “And eight out of 10 times it’s gorgeous.”

“Blue” is a book, at least in form. But it’s really a hand-held exhibition of almost 150 years of music history reflected in the faces, instruments and body language of the men and women in its pages. Dave McGrew, who followed the fruit harvest as a picker, doing a day’s work for a day’s pay and making music in the evenings. Captain Luke grew up hauling scrap in South Carolina, eventually using his deep, natural baritone to master country blues. Algia Mae Hinton, whose mother taught her music during breaks from farm work. She would go on to support her own children in the same way, keeping her music alive and passing it on. Freeman Vines, a self-taught luthier who makes instruments out of found materials, like a guitar made from an old walnut tree where several people had been lynched, including one in Mr. Vines’s own lifetime.

Steven Albahari, the book’s publisher, said that its design reflects its content. There are only 10 books in each printing, and they go for $17,000 apiece. Each has a hand-painted cover, its pattern inspired by the quilting traditions of Gee’s Bend, Ala., where the Rev. Dr. Martin Luther King Jr. spoke on the eve of the Selma March in 1965. Each edition has an original tintype plate, each heavy-gauge page is made in Indiana using worn-out denim jeans, giving it a very faint bluish cast. Turning the pages of “Blue” is to turn those of a history rarely told and one to which modern American music owes nearly every note.

Mr. Duffy said a lot of “white outsiders” like him have visited or spent time with different cultures, but he believes if you look at their work “you can see the baggage that they bring in,” and the end result can feel like a caricature. He mused that he might have some elements of that too, but is aware of the danger and tries as much as possible to disappear from the process.

“How as an artist can I honor this experience and get people to feel and get a sense of what I look at?” Mr. Duffy said. “When I see them, this is what I see.”

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READ THE ARTICLE ON NYTIMES.com HERE – http://nyti.ms/2sXqPYp