Brian May might well be best known as a virtuoso musician of world renown, and most of us will be aware that his doctorate is in astrophysics, but he is also a world expert on early stereographic photography technology.
As has happened so many times for this legendary guitarist as the lights dim, the crowd settles into impatient and yet hushed expectation. Brian May saunters onto the stage followed by two colleagues. He takes to the lectern flanked by Denis Pellerin and Paula Fleming, makes a joke or two, and introduces the subject of this evening's lecture: 19th century stereoscopic photography. As odd as it might seem, May and his co-authors are launching a new book on historic 3D imagery at the British Library to a select band of a few hundred enthusiasts.
'Diableries: Stereoscopic Adventures in Hell' is May's second publication on what is now an all-but forgotten art form (his first was his rather bucolic 'A Village Lost and Found', which celebrated the work of British stereographic pioneer TR Williams). "It's been a dream of mine for decades to bring stereo photography to London," he informs the audience. For a man who has lived under the spotlight of soaring international success as a musician for most of his adult life, this might at first glance appear something of a modest dream. But, as the curiously gothic event progresses - it was held on the eve of Halloween - what becomes clear is that May is deadly serious, and his dream could well be more accurately described as an obsession.
Speaking with May a few days after the British Library event, he tells me how stereographic projection, or stereoscopy, is the technical process by which 3D images are created in the brain as a result of the fusion of almost identical images that have been marginally offset and viewed through a binocular instrument. The technology has been around since the dawn of photographic time, with the first sets of experimental stereographic plates produced in the 1840s.
For the Victorians, crowding around the stereo viewer was a wildly popular form of entertainment that May compares with modern television. Today, the card sets that go with the original viewers are hard to come by, but if you know where to look you'll find them on subjects such as early geographical expeditions to Greenland or North America, or even quaint villages in Oxfordshire. But May's new book is about a collection of card sets that have been dubbed the 'diableries' (or, 'devilments'), and they are pretty diabolical.
"Stereoscopic images are by their very nature astounding because they have incredible depth," says May. "The compositions are stunning, not just because the eyes light up, jewellery glistens and lanterns glow. We're looking at a whole parallel reality populated by skeletons getting up to all kinds of mischief. Add to that the political satire that is embedded in these tableaux, and you have something very special indeed." And spooky. There are devils and dervishes everywhere - even the book's cover has a gold embossed flying demon playing a rather diabolical looking trumpet stamped on it. The Victorians loved spooky stuff.
May says that his interest in stereoscopy started when "it reached out and grabbed" him as a kid. "I was very inquisitive and I used to lie under the covers of my bed with' one eye sticking out, pondering why my brain was receiving two different images. And this led to a curiosity in that direction."
May recalls how in his youth the VistaScreen cards that came with Weetabix breakfast cereal fascinated him. You needed a viewer, but May worked out how to look at them in 'free-view' by either defocusing or crossing his eyes. But you could also (and he did) send off for a stereoscope that would set you back one shilling and sixpence (7.5p) in the form of a Postal Order. "I figured out very quickly what they were doing to achieve 3D images, and that fascinated me, as it has done ever since. It's such a simple principle, and yet no-one can tell you physiologically what's going on in your brain when it puts the two images together to make a stereoscopic map of the world in your head."
May soon became aware that stereoscopic imaging was one of the earliest forms of photography, "and I discovered that all the pioneers of the technique were not simply technologists, but also artists. And I think that's the great Victorian spirit. There's no real hard dividing line between art and science. And that's the way I am too. I think great art should be married to great science, because that's when great things happen".
The images themselves take the form of two treated photographs printed on tissue and mounted onto card frames; the treatment often being hand tinting, or the addition of coloured gels. May recalls finding some in junk shops as a young man, sparking a 40-year obsession with stereoscopy. "You've got to remember that the Victorians had no phones or films. So these images really were the only window into the world. You'll find cards dealing with every topic under the sun, but we chose the diableries to channel the technology into the 21st century."
May says that if you want to put a precise date on the origin of stereoscopic portrayal of photographic images you need to go back to 1838, when the extraordinary English inventor Sir Charles Wheatstone first described 'stereopsis'. This led to him receiving the Royal Medal of the Royal Society in 1840. But others were working along similar lines, including David Brewster and a certain Mr Eliot, a mathematics teacher from Edinburgh. "This was exactly the time," says May, "when Fox Talbot was discovering his process in England (calotype), and Louis Daguerre was discovering his in France (daguerrotype)." As is so often the case in technology, competition bred innovation. The race was on, and stereoscopic photography was born.
The aim of stereoscopy is to reproduce the experience that you would have "if you were actually there", says May. "Suppose you are sitting in front of a tree with your stereoscopic camera: what you want to do is reproduce that as closely as possible. What the stereoscopic camera does is to take one picture corresponding to what your left eye is seeing, while the right lens of the camera takes a picture corresponding to your right eye. And then all you have to do is ensure that the left image is presented to the left eye and vice versa without any cross-talk."
The Victorians viewed their stereo images through a stereoscope, which May claims is still the best way to fuse these offset images. Not content with tracking down early examples of these instruments, he decided to invent a modern one so that his readers could enjoy the best possible experience from his books. His 'Owl', which he designed on behalf of the London Stereoscopic Company (of which May is a director), is a singe flat piece of mass-produced injection-moulded plastic containing two magnifying lenses and folded twice at 90 degrees to form the viewer.
"The idea is that you're hardly aware that the image is happening. All you are aware of is that you are getting the same experience that you had when you were sitting under that tree." May continues by saying that viewing stereoscopic cards as the Victorians did, through an instrument such as the Owl, is a much richer experience than watching 3D movies in the cinema through cyan and magenta anaglyph glasses. (Which is something of an irony, as this was the compromise technology May adopted in order to demonstrate his diableries in 3D to his audience at the British Library.)
May's first book on stereoscopic photography - 'A Village Lost and Found' - was very much the template for the diableries. "Everybody seemed to relate to it very easily. They got their Owl viewer and the book, and the printed images in the book were of high enough quality for them to be experienced directly off the page," he says. "That was one of the hardest technological problems to overcome really, because even high-quality art books are screen printed and if you look at those screen prints under high magnification through the Owl, all you can see are dots. So the first thing we had to do was to research whether there was a way of screen printing the cards that didn't produce a distracting dot effect."
May and his team were soon led to a process called stochastic screening, a halftone process that differs from traditional amplitude modulation screen printing in that the geometrical arrangement of the dots is based on pseudo-random distribution rather than fixed spacing. Even going down this route, May discovered that his eventual success in reproducing the stereo cards would depend on who did the printing for him. "We found this wonderful quality printer in Italy, who'd go to endless trouble to get the absolute best out of their stochastic process. I'm really thrilled with how the images came out. I don't think there's ever been a book with image quality such as we've managed to produce in the 'diableries'."
May says that the reason he was able to keep such a firm grasp on production values was because "this time I was the publisher, which means that I got to say how the book was printed and bound, how the slipcase was made and how the cover was done. We've gone to ridiculous extremes to ensure that the production values are high".
What this means in business terms for May is that it will be "hard for us to make a profit on this book. But I really don't care. I just wanted the best quality book out there.
"But," he continues, "this is a dream of mine to bring this wonderful imagery into the public eye. It's such a great experience to see these diableries that I wanted to share it. Even if you could reproduce the cards - which you can't with 21st Century technology - you've still got to supply a viewer. But it's not just about entertainment. I needed the book to be a scholarly work, and the key to that was to bring in Denis Pellerin, the most extraordinary photo-historian I have ever come across. Denis was able to go into all those dark corners to find out what these images really mean".
In the 21st Century, when many movies are made digitally in 3D, if a director can imagine something, then the technology can be harnessed to bring the vision to the screen. So with all this high-tech wizardry at every turn, what is it about this comparatively low-tech photography that appeals so strongly to May?
"Well, first, I wouldn't say that it is low-tech' it's just different and delicate and complex. If you tried to reproduce a diablerie with 21st Century technology, I'm pretty convinced that you'd fail. I can say that because I've tried it."
May confesses that he is something of an analogue loyalist, both in photography and music. The early Queen LPs carry a sleeve note proudly explaining the band did not use synthesizers, digital or otherwise; while today "there is still a place for analogue in music. And this is because we as human beings are analogue creatures. We're not built from ones and zeroes. I tend to think that we will return to analogue at some point, which is an irony in a sense because I'd never have been able to make this book without using digital technology".
Without image editing and restoration software, May reflects, the 'diableries' would have been a collection of grubby and dirty images. "And I thank God for Photoshop, so that I could take the images into the digital world, work on them, and then reconvert them back to analogue so that I could present them in the book. And what you see is pretty much exactly what the Victorians would have seen. But I do love the old technologies. There's an intimacy and warmth to it. And really, there's nothing quite like looking through a stereoscope."
And so what does the future hold for Brian May's adventures in stereo photography? "There are so many books that I'd like to write on stereoscopy. Maybe one on the pyramids of Egypt. That would be great."