WHEN Robert Burley began documenting the global implosion of the silver-halide roll-film industry in 2005, he used an analogue camera. A digital one would have been a quirky choice for his style, unable to deliver the same precise results he was used to after decades of photographing architecture and landscapes. But as Mr Burley's journey progressed, he watched the ecosystem of film rapidly dissolve around him. "I was starting to feel like a blacksmith," he says, recalling the large-format camera kit he would unpack in order to capture his waning industrial subjects. The final result of his efforts, "The Disappearance of Darkness", is a book full of poignant insights, both visual and literary, into a bygone technological era. Mr Burley, an associate professor at Ryerson University in Toronto, did not set out to write this book. Rather, he heard in 2005 that Kodak would shutter long-standing Canadian operations in his city. So he asked the firm if he could take pictures of the plant. This turned into 18 months in which he documented the layoff of workers, carting off of plant equipment and destruction of buildings. That was the beginning of the end for Kodak. In 2007 Mr Burley travelled to watch the implosion of buildings in Rochester, New York, where George Eastman founded the company in 1889, four years after having invented roll film. (Eastman lacked all the necessary patents, for which he later paid dearly.) The same year he visited Chalon-sur-Saône, a French city north of Lyon, where the first known photographic print was produced in 1827, and where Kodak settled its European operations in 1961. Kodak tried to bring down its primary building there in December that year. It refused to be blown up. A second set of charges was required a few months later. In 2010 Mr Burley went to Dwayne's Photo Lab in Parsons, Kansas, the last place in the world to process Kodachrome, as it handled the final rolls. Even so, film refuses to die. But neither can be it resurrected, says Mr Burley. Kodak's bankruptcy filing in January was a result of decades of mismanagement. But it was also the victim of rapid technological change for an industry based on chemistry and large-scale production of an obsolescent good. The spike in silver prices was no help, either, for a product that must needs use it. (Your correspondent, who once worked for Kodak, witnessed it fritter away the technological lead it held in 1991.)

Consumers and professionals ditched film first. Then health-care services, which used it for X-rays, shifted to digital scans. The final blow came with the film industry's switch to digital projection. IHS iSuppli, a supply-chain analysis firm, estimates filmmakers consumed 2.5m miles (4m kilometres) of film each year for the distribution of prints at its height. That was just a few years ago. By 2012 this plunged by two-thirds. In 2015 it will be next to nothing. Mr Burley says that after years of talking with the workers, chemists and engineers that ran the plants he foresees a tipping point beyond which consistent quality photographic film will be impossible to make because of the scale necessary to maintain operations.

That point has not yet been reached. Polaroid factories in Massachusetts may be abandoned, but those in Enschede, the company's former European headquarters in the Netherlands, live on. That is thanks to the Impossible Project, which aimed to reboot instant-film production using original equipment (as well as a fair amount of reverse-engineering, or reinventing, lost secrets). With the expertise and hard work of a handful of people it succeeded, and has shipped millions of units of print film, including new variants that go beyond anything Polaroid made. It relies partly on Ilford, a British manufacturer of black-and-white film based in Mobberley (and also documented in the book). Ilford has so far survived bankruptcy and upheaval. But the Impossible Project as a whole depends on ancient equipment, a limited term lease and chemicals and processes provided by other firms.

Mr Burley showers praise on the Impossible Project. Yet it could only succeed because its product need not be consistent. Compared to standard photographic film, each instant print is messier and unpredictable. It is the exception that proves the rule, he says.

The youngest crop of his students, all digital natives, have never touched analogue film. So, despite embracing (and teaching) digital photography, Mr Burley also developed a course, now in its third year, which recaps the history of photographic processes, from glass plates to the present day. It is exotic for them to spend the day working slowly with their hands instead of in front of a digital screen, he says. The instant availability of digital photographs means students are never surprised by what they make. The course lets them appreciate the "objecthood" of the photographic image.

Photographic film has nearly completed its transition from the mass market to the artisanal. Memories of analogue film fade each year. Older folk pass away, materials become more expensive and developing labs close. And darkrooms let in light.