Photo-London
How We Are: Photographing Britain

Two blockbuster photographic surveys in London cover some of the same ground, both giving some sort of overview of photography in Britain; but they could hardly be more different from each other. At Tate Britain, their first ever large photography exhibition 'How We Are: Photographing Britain' offers a history of this subject from its beginnings in 1840 up to the present day (see below). Meanwhile Photo-London brought together what the participating galleries hope will be this year's top-selling photographic prints. How We Are runs until 2nd September 2007, and is dimly lit to conservation standards, while Photo-London shone with super-bright daylight-balanced spotlights for a brief four days at the beginning of June, and is an annual event; its older sibling event, Paris Photo, takes place 15-18 November.

Photo-London is unashamedly about sales. Everything on show is available to buy, and while the prices might look high to someone on the minimum wage, if you're the kind of person who regularly buys a new car, you could instead hang on to the old banger and become the proud owner of half a dozen stunning photographic prints. And in theory, you'd be ahead financially too; at a panel session on collecting photography, market expert Jeffrey Boloten described how photographic prints have increased in value over the last two decades more than almost any other investment. The advantage of buying at Photo-London is that the galleries have staked their reputation on the continuing value of the work they sell.

But don't just buy because you think something will make you money. Francis Hodgson of Sotheby's described the confusion and overlap between collectors and investors; and has met many aspiring investors who fell in love with their collections. Meanwhile the true investors might buy an entire edition of a famous photographer's work and stash it away in a bank vault while its value goes up. Instead, as wily collector Bill Hunt observed, watch the hair on the back of your hand. If it's standing straight up, buy the photo. Hunt admits to difficulty selling pictures; no doubt his heirs will thank him for that, but there is not much liquidity in photography.

Is all of this good for photography generally? Hodgson is the first to admit that only a very thin slice of photographic activity is considered by the collectors and investors who attend Photo-London. If you want to succeed in this sphere, it helps a lot if your work fits. We're talking sumptuous, visceral, big photography here, that's going to look good on someone's wall. Notably absent from Photo-London was the visual asceticism characteristic of certain high-brow conceptual photographic artists. Even so, your ideas have to be strong, original and somewhat consistent too.

Just as important as the quality of your work though, is how you market yourself. You ideally need to have a name that a buyer recognises and can rely on, and you'll have acquired this name because you have committed your career to being taken seriously as a star photographer. You need to be careful about managing your limited editions, and don't cheat by making a new edition that's an inch bigger than a previous one but otherwise identical, or by producing forty artist's proofs for each edition. All of this could be managed by your gallery, but acquiring one of those is often a long-winded task that involves bringing yourself to their attention without actually approaching them direct.

If you're the kind of democratic soul who celebrates an image's ability to be reproduced indefinitely and seen by everyone on the planet, does that rule you out? Well not necessarily it seems. Photo-London included many who are known for popular editorial photography - Don McCullin, Stephen Gill and Simon Norfolk to name a few. Insiders argue that it's the very accessibility of photography that makes it so appealing to collect; and the Gursky work (99 Cent II Diptychon) that recently sold for a record sum, has been widely seen through being reproduced in newspapers and magazines. For all this to work, the distinction between what Hodgson calls the object and the image needs to be preserved; the limited-edition photographic print is the object that appeals to collectors, while the endlessly distributable image is the intellectual property in the photograph that earns its usage fees.

Nevertheless it's an irony that won't be lost on thousands of struggling editorial photographers that the increasing value of this narrow stratum of work is not reflected more broadly in editorial commission and library rates, many of which are at their lowest levels in decades. It's becoming increasingly important for all professional photographers to investigate and consider participating in the world of print sales and the art market.

It's very pleasing to see that day-to-day editorial and vernacular photography form a central part of How We Are, at Tate Britain. One of the many heroes of this wonderful exhibition is Charles Jones, the gardener who obsessively photographed fruit and vegetables at the turn of last century, but then re-used the glass negatives to make cloches for his tender plants. In fact it's this exhibition's own 'cloches', the many display cabinets and video screens containing magazine, book, album and project photography, that really give depth and weight to the selection.

Picture Post is there of course, but so are Good Housekeeping's cookery photos, and The Rose Annual; The Sunday Times magazine (pairing Paul Foot and Leonard Freed) sits near to Camerawork's influential 8th issue, 'Lewisham: what are you taking pictures for?', which includes some revealing interviews with political photographers (although you can't see them in the cabinet). There's very little in the way of sensation and celebrity; how much more enjoyable are the anonymous subjects of Daniel Meadows taken on the tour of the Free Photographic Omnibus or of Grace Lau in her Shanghai gallery recreated in Hastings.

Near the end of the exhibition are some enormous portraits by Alastair Thain showing soldiers straight after heavy exertion, but the curious effect, since they are dark pictures behind glass, in a fairly tight space, is that we see our own reflections quite clearly. I'm not sure if this is intentional but it leads rather neatly to screens placed outside the main gallery that give members of the public the chance to be part of the exhibition. Already (three weeks after the show opened) 4,000 have been submitted, but just 40 will make it past the selectors to be displayed in the gallery in the last month of the exhibition. This will give everyone the chance to compare their own judgement with that of the selectors, and also a taste of how difficult it must have been to put the main show together.

With the subtitle 'Photographing Britain' the curators have implied the limits of their selection. Every picture adds to their particular portrait of the people and places of this country. What emerges is an exhibition with a clear personality, recurring themes, and a story to tell about the way Britain looks - and a startling sense of visual resonance over the last century and a half. There are inevitably omissions, but this show should still be essential viewing for everyone with an interest in photography.