"What I’m looking for is that fraction of a second that at least I could remember the concert by." At the start of the 2013 BBC Proms season, photographer Chris Christodoulou let theartsdesk into the secret of snapping conductors at work. Now that the Proms are over for another year, we publish not the official shots, but the ones which are simply too quirky to be released by the BBC press office. These images may not particularly flatter their subjects, but they do capture what it is to be a silent maestro magically conjuring sound from the massed ranks of an orchestra.

In a couple of weeks Marin Alsop will become the first woman ever to conduct the Last Night of the Proms. Yesterday's programme of 19th century works by Brahms and Schumann, on the fifth of the eight Saturday nights of the season, thus had its Proms-specific raison d'etre, a signpost towards that history-making final Saturday. Just as the last night's high jinks have their own, ordered traditions, the Proms planners definitely enjoy giving a self-referential logic to the season.

By the time silence descends on the Royal Albert Hall at five o’clock in the afternoon for a performance that will end six hours later, Semyon Bychkov will have been rehearsing for 60 hours. It breaks down into four days of orchestra readings, with tutti and sectional sessions for each act, then two days of the singers and a pianist, followed by six days of everybody together. And all for one performance of Tristan und Isolde with the BBC Symphony Orchestra.

Chris Christodoulou has been photographing conductors at the BBC Proms since 1981. Many attending the Proms at the Royal Albert Hall may well have attempted to spot him. They can give up on that game herewith. As he explains to theartsdesk, the venue with its many curtains and nooks allows him to work discreetly. (If you want to know what he looks like, see below right.) We have been featuring Chris’s pictures in an annual gallery since 2010. This year we have asked him what makes a good picture of a conductor, and how he goes about securing it.

It’s only fitting that Sir John Eliot Gardiner should be celebrating his 70^th birthday with a concert in the Royal Albert Hall. That it should be a nine-hour marathon of a concert is not only fitting, but entirely predictable for a musician who has always kept one eye on the next and biggest challenge.

In many ways the most well-tempered of conductors, Wolfgang Sawallisch (1923-2013) brought a peerless orchestral transparency and beauty of line to the great German classics. Even the most overloaded Richard Strauss scores under his watchful eye and ear could sound, as the composer once said his opera Elektra should, “like fairy music by Mendelssohn”.

Sir Simon Rattle (b. 1955) and the Orchestra of the Age of Enlightenment (est. 1986) have been together from the beginning. Founded by period-instrument musicians eager to run their own affairs rather than play obediently for conductor-managers like Christopher Hogwood and John Eliot Gardiner, the OAE invited Rattle to conduct a concert performance of Idomeneo in that first year.

Lehár’s Merry Widow has been been spreading enchantment across the globe for well over a century. She’s the vintage champagne of operettas, and the prospect of John Wilson popping her cork was more than a little enticing. Wilson, one feels, instinctively knows how this music goes and indeed did so before even the composer put the notes on the page. He was surely born into the wrong century. So why do I feel a "but" coming on? Why did this particular magnum of bubbly not go to my head?

The BBC Proms are steeped in traditions, many admirable, some arcane, the odd one ever so slightly maddening. In the short life of The Arts Desk - we turned three on Sunday, the day after the 2012 Proms season came to a close - another tradition has come into being. Every year we publish a gallery of portraits of conductors at work. These astonishing photographs are all by Chris Christodoulou, who has been capturing the Proms in pictures for 31 years.

The greatest music festival of them is once more upon us. Throughout our extensive coverage of last year's BBC Proms, we featured the remarkable work of photographer Chris Christodoulou. We have asked Chris to select his favourite pictures of conductors at work, and we present them again for your entertainment and enlightenment as the world's greatest conductors again take to the podium for the summer to show exactly what it takes to do what they do.