When Karl Lagerfeld joined Chanel in the 1980s, he was so picky about the advertising photos on offer he was told to go shoot them himself.
He took the bait, kicking off a love affair with the art form.
"Back in those days, press photos for fashion collections existed, but they would be shot either by beginners, or has-beens," he told AFP ahead of the opening of a major exhibition of his photography in Paris.
"One season, in 1987, Chanel's image director showed me one, two press packs - and at the third he said, 'If you are so difficult, why don't you do it yourself'," said the German fashion maestro, now in his late seventies.
To begin with he was, he says, "an absolute beginner, like people who snap pictures with their mobile phones today".
But the experiment took off - and with it grew a passion for alternative and in some cases long-forgotten developing techniques, and their effects on grain, colour and texture, all on ample display in the Paris show.
For six weeks starting Wednesday, the French capital's Maison Europeenne de la Photographie is exhibiting some 400 of Lagerfeld's images, shot around the world, "mostly with a basic little Fuji, that I can carry around with me."
"I used to be so involved with the clothes world, with my nose right up against it," says the designer. "I feel like it widened my vision. I can see things more clearly."
"What interests me, what I am passionate about, is the different developing techniques, all that we can do - and what we can no longer do. It is as important as the photography itself."
New York cityscapes hang beside semi-abstract shots of landscapes or buildings - from the Versailles Chateau to a snowstorm in Rome - the latter printed on long loose strips suspended like wallpaper.
Next door, fashion and advertising shots rub shoulders with a kaleidoscope of mostly black-and-white portraits - an A to Z of the film and fashion worlds, from David Lynch to Nicole Kidman or Gerard Depardieu.
But for Anne Cartier-Bresson, who restores old photographs for the city of Paris, the images stand out most for their work on texture and pigment.
"Karl Lagerfeld is not a fashion photographer at all - he is a real creator. He chooses his photographic materials like you would choose fabric."
In one case this involved reviving a rare 19th-century technique called the resinotype process - "diabolically hard to do" according to Lagerfeld.
For other works, Lagerfeld painted on the pigment himself - using Japanese-made eyeshadow for its range of colours and extra fine grain.
"I love it - you are working on tiny little prints. It is painstaking work, square millimetre by square millemetre."
At other times, however, Lagerfeld is happy just to let the images speak for themselves.
Pointing at a portrait of Jack Nicholson, in black and white with a glaring red t-shirt, he quips: "It looks like it's been fiddled with - but for once it's not. The sun was so bright, that's the true colour."
On the modern-day use of Photoshop or other software to doctor images, in the fashion industry and beyond, Lagerfeld is polite but dismissive.
"One day Claudia Schiffer was telling me about a photographer, whose name I will not reveal" he recalled. "She said: they take someone else's arm, another person's head - I was ugly with bags under my eyes, now I look gorgeous."
"You start with something awful, and it becomes a wonder. In the end it all comes out looking the same."
Lagerfeld's photography blossomed into a full-fledged career pursued in parallel with his design work for Chanel, Fendi and his own label. Now, he says, the two arts feed into each other "in a kind of stimulating bulimia".
In an industry that collectively disappears on vacation when the catwalk season is over, he says, photography has also been a way to join things up, to avoid the "emptiness" in between collections.
"Now, since I head straight into advertising and editorial work, there is constant dialogue between me, fashion, photography, everything."
Lagerfeld says he hopes there is a common "spirit" running through his work. "But I don't want it expressed the same way every time. I would just find that so boring."