Photography:Minas Gerais Pump House Gallery / Bolivar Hall, London

The people of the Brazilian state of Minas Gerais are the Yorkshiremen of the Western Hemisphere, the Normans of the New World; hard, no-nonsense individuals who have, over the centuries, made a great deal of brass from the mountains of muck they have dug out of their "General Mines". The Mineiros affect the same disdain for the effete society of Rio de Janeiro as the people of Barnsley display towards the residents of Belgravia. At the same time, they are as proud of the natural and man-made beauty of their state as Yorkshire men are of Wharfedale or Castle Howard.

Great material, one would think, for the three photographic exhibitions that were mounted as part of the Festival of Minas, the month-long show of the state's arts in London. But success has been variable.

Beside the lake in Battersea Park, the tiny but pretty Pump House Gallery has a show of pictures of rural life by Marcelo Ferraz. It captures some of the more traditional peasant aspects of the interior of Minas: solemn working cowboys, simple interiors, scenes of a country circus. Particularly pleasing are the photos of rural architecture, showing roofs with tiles bearing a design from Julius Caesar's Rome, which came to the heart of colonial Brazil via Portugal. This is a small but reasonably satisfying show whose exotic quality is heightened by glimpses of London parkland through the windows.

Despite having no less attractive subjects, the other two shows were much less successful. Bolivar Hall, the exhibition space and auditorium that the Venezuelan Embassy built some years ago beside Warren Street Tube station, presented the most outstanding object lesson given in London for many years in how not to mount an exhibition.

The first show, of pictures by Rui Cesar, had as its subject the wonderful Baroque architecture of the state, one of the artistic marvels of the Western Hemisphere. Ouro Preto, the town of black gold, was once the capital of Minas and from its mines flowed the gold and diamonds that made the 18th-century kings of Portugal the wealthiest in Europe and also added to the coffers of the City of London. The second, put together by Danilo Matoso and Ascanio Merrighi, was of the early 20th-century Belo Horizonte, the state's capital, a Brazilia of the 1890s. Both sets of photographs were stuck up on the badly lit walls of a neglected basement.

The tired and blurry prints, many of them with the fuzziest of focus, gazed at each other from the opposite walls of the hall. There was virtually no attempt to present or explain the subject-matter. The lack of imagination with which it was done would disgrace a prize day at a kindergarten.

Given their obvious lack of expertise, those involved in mounting these two shows would have done much better not to have attempted the exercise in the first place. A good opportunity missed.

n 'Royal Architecture of Minas Gerais: 40 pictures by Marcelo Ferraz' is at the Pump House Gallery, Battersea Park, London SW11; 11am-6pm Wed- Sat to 14 July