Two magnificent earth-moving grabs are poised at odd angles on the ground, their connecting rods silhouetted against a uniform sky. If it weren’t for the characteristic tones and surface of an albumen print, you would be sure it was a modernist masterpiece by some 20th-century poet of steel. But it is anonymous, it comes from a functional engineer’s report on the construction of a dam in Bihar, India, and dates from 1871. Points of View: Capturing the 19th Century in Photographs, the British Library’s first devoted to the photography in its own collection, is crammed with delights of this kind. There are famous photographs, too, but the quirks steal the show.

‘Hippopotamus at the Zoological Gardens, Regent’s Park, 1852’ by the Count of Montizón

For example, the anthropometric photographs made by Maurice Vidal Portman, a colonial official, in the Andaman Islands in the 1890s. His platinum study of a scarified torso, cropped below the head, is a great nude. The ritual scars catch the light and modulate it as it falls across the curves of the body in a way that compares elegantly with the shadow contoured nudes of experimental photographers such as Man Ray and Erwin Blumenfeld a generation later. Yet Portman was no photographic sophisticate. In two other colonial studies of his, the hands holding the chequered backboard are visible to the left and right of the pictures like accidental symbols of control itself.

There are about 200 photographs in this show, which is divided thematically into a large number of relatively small sections. These are nominally on the development of photography itself – on, for example, “the quest for permanence” or “testing the market” – while allowing the curators to look at the whole century through photographers’ eyes.

The mixture of motives and methods is fascinating: photography really did seem to provide all things to all men. So here, within the first 60 or so years of its existence, sometimes in coarse early forms and sometimes finished to a high polish, are war photographs and social documents, scientific advances and arty manifestos. Here are wide and telling variations in size and chemistry, as well as in purpose and audience.

One of Maurice Vidal Portman’s Andaman Island portraits, c1893

The profusion is itself a pleasure, but it also prompts some questions. We’re in 2009, far too late properly to cover the whole development of photography in a single show. Many of the subsections here could merit or have already merited whole exhibitions and books of their own. That photography was born and boomed in the 19th century is a surprise to nobody. The real purpose of the show is not so much to tell us what photography is or has done – although it does some of that admirably – but to let us know that the British Library is one of its great treasure-houses. This, surprisingly, will be news to many.

Not only has the library never before had a major photographic exhibition, but for many years its curator of photographs, John Falconer (now more grandly titled Head of Visual Materials), was not funded directly by the library but by grants from outside agencies. For him this exhibition is a triumph. It means his superiors are prepared to enter the confused waters of the UK’s photographic institutions and in so doing alter the status quo between such places as the V&A, the National Media Museum in Bradford, Yorkshire, and parallel bodies in Scotland and Wales.

And Tate, which for years spurned photography, is turning its gaze upon the medium’s crowd-pulling power and has recently appointed its own curator of photographs.

The British Library’s exhibition itself is a treat. It has some unfortunate designer tics, of which pointless giant enlargements of photographs and engravings relating to photography are the most egregious. It also bites off more than any single exhibition could hope to chew and treats many very important aspects of its subject too slightly. But it compensates by the magnificence of so many of the exhibits.

A plate from Loewy and Puiseux’s lunar atlas

The whole history of the library’s involvement in photography has come (obviously enough) through books. It is rare to find so few framed single images and so many whole volumes displayed instead. We are used today to books containing printed reproductions of photographs. The 19th-century norm was different. The books here contain photographic originals, and much effort went into discovering and exploiting ways of making reproduction easier or better. From Fox Talbot’s own little notebooks (detailing the proto-history of photography) to huge early photographic folios, the variety of types of publication would merit a study in its own right.

They present a problem of display in that only a single spread can be seen at once, but careful use of mini-slide shows allows visitors to “turn pages” at their own speed. Among rare old favourites that anybody would be glad to meet or meet again, I would list first Gardner’s Photographic Sketchbook of the [American Civil] War, from 1865, as much an entrepreneurial masterpiece as a journalistic one. Especially noteworthy too is Loewy and Puiseux’s almost incredibly ambitious atlas of the moon, only finally published in 1910.

The title of this exhibition – Points of View – hints at a certain diffidence in taking a single clear position on its vast subject. To see so many original volumes, known and obscure, may in the end be the simple enough point of an exhibition that signals the welcome public debut of one of the world’s great photographic collections.

To March 7, tel 0870 444 1500