(CNN) Ebony and Jet magazines were once pinnacles of black American culture. Their photographs were windows into intimate moments of black celebrities, and they were known for their everyday depictions of middle class black life, especially Ebony magazine.

"It was Ebony that took to remind America of black people's humanity," said Jeffrey McCune, a professor of African and African American Studies at Washington University in St. Louis . "It colored black life in spectrum."

A significant portion of that legacy is changing. Both Jet and Ebony still exist, though only Ebony continues to produce a print product. But their former parent company and owners of the photo archive, Johnson Publishing, filed for bankruptcy in April

Now, the historic archive will be up for auction on July 17, with the dues going toward the creditors of Johnson Publishing.

Carmen De Lavallade and James Truitt perform on stage in this undated photo. (Howard Morehead/ Johnson Publishing Company)

Muhammad Ali is photographed with Howard Cosell backstage before "The Muhammad Ali Variety Special" in July of 1975.

The archive contains photos from 1945 to 2015, with about 1 million printed images, 3 million negatives and contact sheets, and several thousand hours of video footage.

Some photos have never been printed and thus have never been seen by the public. Very few have been digitized. But the collection holds, among many more prized photos of black legends, the 1969 Pulitzer Prize winning photo of Coretta Scott King and her daughter at Martin Luther King Jr.'s funeral.

In total, the archive is worth around $47 million.

Frank Robinson takes a few swings during batting practice in this undated photo. He was the first African American to manage a team in the major league.

Actor Raymond St. Jacques -- pictured in 1969 -- was the star of several blaxploitation films.

Bids are expected to start at around $13.5 million -- the outstanding amount Johnson Publishing owes the Capital V Holdings, owned by filmmaker George Lucas and Mellody Hobson.

Gabe Fried, CEO of Hilco Steambank, which is conducting the auction, said the lender is willing to take the archive if the amount isn't paid off. So, if no one bids, the lender will get the archive in a foreclosure, but Fried says an auction will most likely be held.

"We've received a number of strong expressions of interest from well qualified parties," he told CNN.

Johnson Publishing no longer owns its two hallmark magazines, after selling them to Clear View Group in 2016. The company previously tried to sell the photo archive in 2015, but was unsuccessful.

What will happen to these photos?

There's no telling what will happen to the archive until the auction, and the uncertainty weighs heavy.

McCune grew up reading both Ebony and Jet in Chicago -- seeing the new copies waiting on the dining room table. At the time, he said the magazines gave him access to the culture he didn't see reflected on television or in other publications. They changed his life.

Ebony, he said, was the most significant depiction of black life in the 20th century.

"I really fear that what we will have is that some collector will take it into their private collection and cut it off from public access," he said. "The beauty of Ebony is that Ebony was a public gem."

Rockstar Jimi Hendrix is photographed in London, England.

Ruby Dee and Ossie Davis stand outside of a theater in 1959.

Whoever, or whatever, owns the photos after July 17 will have a weight to bear. These photos aren't just photos -- they're history.

"If these images are lost, if these images are privatized, if these images are somehow destroyed, I think that that type (of loss) is unaffordable," McCune said. "There is power in preservation and, particularly for black life in this country, visual representation is important."

Clark Terry plays the trumpet with his son Rudolph and Duke Ellington in 1955.