“Steinberg was looking at copies of famous works, and how they helped reveal the artist’s choices and intentions,” said Holly Borham, an expert in art prints and a curator at the Blanton Museum of Art in Austin. Borham spoke with me about how the art critic Leo Steinberg, who broke ground in the 1960s with his ideas about pop art and Renaissance masters, arrived at his discoveries through his giant collection of art prints.

“Those prints helped him to get new insight into artists like Michelangelo and Leonardo da Vinci,” she said. “He uncovered the intentions of the original artists by looking at prints, and that helped him become a towering figure in art history.”

Steinberg’s giant collection of prints – and the theories they inspired – are now the subject of Borham’s new book, The Circulating Lifeblood of Ideas, which offers a fascinating look into the thousands of prints that Steinberg collected over his lifetime. In her book, Borham builds on her work conserving and exhibiting Steinberg’s prints at the Blanton, offering a rare look at his final collection, which numbered over 3,500 prints and covered 500 years of art history. Those copies helped him become one of the foremost critics of his era.

Once declared one of the three “kings of Cultureburg” by Tom Wolfe – Clement Greenberg and Harold Rosenberg were the others – Steinberg established his reputation in the 1960s, when he was among the first to see the value of the pop art movement. The quality of his writing earned him rare plaudits, like a visit to Mark Rothko’s studio, correspondence with artists such as Philip Guston and Jasper Johns, and support from Margaret Scolari Barr, an art historian who was the spouse of the founding director of the Museum of Modern Art – among other things, she gifted Steinberg his very first print.

Borham shared how Steinberg, in part, built his reputation by being the first to use the term “postmodern” to describe the bracingly new art that the likes of Robert Rauschenberg, Johns and others were creating. “It was part of a lecture he was giving at Moma in 1968,” she said. “He was arguing against this teleological idea of art, and he said, ‘Artists now are postmodernist, they’re bringing the world back in, they’re bringing in popular culture, they’re not going into this pure[ly] abstract level.’”

As it turned out, Steinberg’s expertise in prints was a perfect match for the pop art that was taking over culture in the 60s and 70s. Long before mass communications made it possible for individuals all over the world to see an image of a significant new painting, artists had to rely on prints to transmit their artistic innovations across large distances. “There was this whole ecosystem of communications happening across artists,” Borham said, “and if you only look at paintings, you don’t see this communication. Prints are facilitating this circulation of ideas.”

According to Borham, Steinberg realized that pop artists were centering their work on exactly that system of artistic communications, and this led him to become one of the leading art commentators of the 60s. “Thinking about the ways ideas circulated in the early modern period primed [Steinberg] to think about contemporary art of his time,” she said. “Whereas early modern artists hid all those communications, artists like Rauschenberg explicitly made that their subject matter.” Just as literary critics such as Harold Bloom were naming the “anxiety of influence”, Steinberg was bringing words like “hijack”, “raid”, “echo”, “recycle” and “appropriate” to art criticism.

Such insights were the result of the nearly 7,000 prints that Steinberg bought and sold over his lifetime. Steingberg came to prints relatively late in life: he spent his early years fleeing from atrocities against Jews in Soviet Russia and Nazi Germany, eventually landing in New York City after the second world war at 25. Soon after he made his way writing and teaching about art, but he only seriously began collecting prints following a heart attack at the age of 40. “He literally has a heart attack and is told, ‘You can’t do hard work this summer,’” Borham said. “That’s when his print-collecting starts. He recognizes the high artistic value of these objects, and some of them are really affordable, enough so that they fit into his small budget.”

Steinberg got in on the print market early enough that he was able to snap up many bargains before the the price of prints increased in the 1970s. By then, his collection was grounded enough to be a springboard to more expensive pieces. When he died in 2011, he left behind an amazing collection worth millions of dollars, which eventually ended up at the Blanton.

In addition to forming the basis of much of Steinberg’s major writing on contemporary art, his print collection also enabled him to make new insights into canonical figures like Michelangelo and Leonardo.

“Looking at copies of famous works helped him reveal the original artist’s choices and intentions,” said Borham. “He wrote a whole book about The Last Supper. You can’t think of another thing to say about The Last Supper after Steinberg looks at it seven different ways! He actually realized that it’s unclear exactly what’s happening in that painting: is it the moment when Christ says, ‘One of you will betray me’? Or when he says, ‘You’re going to eat my body and blood?’ Nobody before Steinberg was able to see all of those moments together.”

Borham elegantly lays out ideas such as these in her new book, while offering brief pieces of critical insight about dozens of Steinberg’s prints, beautifully illustrated throughout. Rigorous yet also friendly to a beginner new to Steinberg’s world, the book makes for a tempting entry point to the world of fine-art prints.

As a lover of prints, Borham found that Steinberg’s story called out to her on a personal level. “Being a print person, I look back at that era wistfully. I wish I could afford those prints,” she said. “It’s amazing to see what someone with intelligence and persistence could achieve back then. And it was satisfying to see Leo’s glee as the prices escalated and recognizing, ‘Oh, I found something of value!’”

For Borham, finding Steinberg was like finding a kindred spirit, someone who understood prints just as she did. It’s that kind of sincere enthusiasm that’s visible in her work with the critic, and that helps make The Circulating Lifeblood of Ideas such an insightful and successful book. “Leo put into words what I’d been noticing about prints,” she said. “When you look closely at a print, you can see every mark. When you pull a paper from the press, it’s really like seeing a baby being born. It’s this brand new, freshly made thing.”

• The Circulating Lifeblood of Ideas: Leo Steinberg’s Library of Prints is out now