NEW YORK, USA: Eastman Kodak Co's long decline that culminated in a bankruptcy filing on Thursday can be traced back to one source: the former king of photography's failure to reinvent itself in the digital age.

The more than 130-year-old American icon filed for Chapter 11 protection in the U.S. Bankruptcy Court for the Southern District of New York, saying it had obtained a $950 million credit facility to stay afloat while it tries to cut more than $6 billion in liabilities.

The filing was not unexpected: Kodak has already become a cautionary tale for anyone considering a career in business.

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Students at top M.B.A. programs read a case study each year that explores, in painful detail, the strategic mistakes that led to the company's slide as digital photography overtook film.

Unlike peers such as IBM and Xerox Corp, which managed to create new revenue streams when their legacy businesses declined, critics fault Kodak for abandoning new projects too quickly, for spreading its digital investments too broadly, and for a complacency in its Rochester, New York, base that blinded the company from technological leaps elsewhere.

"The seeds of the problems of today go back several decades," said Rosabeth Kanter, the Arbuckle professor of business administration at Harvard Business School.

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"Kodak was very Rochester-centric and never really developed a presence in centers of the world that were developing new technologies," she said. "It's like they're living in a museum."

CRIPPLED BY NOSTALGIA

In 1888, George Eastman invented a machine that captured images on large plates of glass. Not content with that breakthrough, he went on to develop roll film and later the Brownie camera.

His company became a household name by helping Americans record their most important life events, first in black-and-white prints and then in Kodachrome color, coining the ubiquitous phrase "It's a Kodak moment."

In the 1960s, Kodak began to study the potential of computers and made a big break in 1975, when one of its engineers, Steve Sasson, invented the digital camera -- a toaster-sized image sensor that captured rough hues of black and white.

But Kodak did not immediately recognize its mass-market potential and focused instead on high-end cameras for niche markets. Executives also feared cannibalizing their core film sales.

"When (George Eastman) died, he had exerted such an influence on the company that one of the things that Kodak immediately became bound up in nostalgia," said Nancy West, a University of Missouri professor who wrote a history of Kodak's early years. "Nostalgia's lovely, but it doesn't allow people to move forward."

Sony Corp launched its own digital camera in 1981, a development that sent "fear through the company," according to a Kodak case study written by Harvard professors Giovanni Gavetti and Rebecca Henderson. The paper is studied at Columbia, the University of Chicago and other top business schools.

Despite those chills, it was not until a decade later in 1991 that Kodak's first digital product for every-day use hit the market, and it was not a camera, but a Photo CD.

Kodak introduced a line of pocket-sized digital cameras in 1996 with the DC20, but made its biggest push into the marketplace in 2001 with the Easyshare brand. By then, the field was already crowded with products from Canon Inc and other Asian manufacturers.

MISSED OPPORTUNITIES

Kodak said in its filing that it hoped to emerge from bankruptcy in 2013. It tried to restructure in the past by closing 13 film plants and 130 photo labs between 2004 and 2007, slashing its workforce by 50,000.

The loan and bankruptcy protection from U.S. trade creditors may give Kodak the time it needs to find buyers for some of its 1,100 digital patents -- key to its remaining value -- and to reshape the business while continuing to pay its 17,000 workers.

Kodak Chief Executive Antonio Perez, who had once called digital cameras a "crappy business," said bankruptcy was a necessary step. "Now we must complete the transformation by further addressing our cost structure and effectively monetizing non-core intellectual-property assets," Perez said.