The Triumph of PaintingSaatchi Gallery, London SE1; until 2006  Impressionism Abroad: Boston and French PaintingRoyal Academy, London W1; until 11 September  Eccentric, obsessive and slightly mad, collectors have been responsible for most of the art that we see. Now, we have to thank the 19th-century collectors of Boston, Massachusetts, and our own Charles Saatchi. The latter is certainly the most influential collector of the last 30 years and has, therefore, come in for quite a pasting; he has been criticised for his purchases and lambasted for his sales.  We have come, unfairly, to associate him with the cutting-edge originality (Whiteread, Emin, Hirst, Quinn and the Chapmans) of his middle years, overlooking the fact that the early collections often featured American artists - Serra, Twombly, Nauman - who were not particularly groundbreaking. So when his first Triumph of Painting exhibition opened in January, there were howls of disappointment.  The second instalment of this three-part show features six artists (five Germans and one Pole). There is nothing much here to set the world on fire and, as a punter, the £9 entry fee seems a bit steep (the old gallery in Boundary Road was free), particularly as Saatchi's County Hall landlords urgently need to install air-conditioning.  The hang opens and closes with the quirky but very approachable work of Dirk Skreber. Saatchi has always been drawn to the slightly macabre and sinister and the Düsseldorf-based Skreber's huge, people-free canvases feature crumpled cars, trains about to crash and tornado-hit bungalows in an empty, hellish landscape. A car lies wrecked on a crash barrier surrounded by the scattered parts of a motorbike, but, mercifully, there's not a body in sight. In the foreground of an adjacent picture, three cars are wrapped round two poles that disappear vertically out of the top of the frame, imbuing it with the inappropriately festive air of dodgems.  Kai Althoff produces equally uneasy work and is obsessed with his crotch. In one work, two soldiers are stealing the boots from a prone victim whose genitals (clothed) are the visual focus, while a dog noses the crotch of a soldier. In another nightmarishly orange canvas, an etiolated soldier in the style of Egon Schiele yanks at his unconscious companion, crotch again to the fore.  Franz Ackermann's hippy-trippy, bright dreamscapes of elevated roadways and loopy staircases are an altogether cheerier proposition, reminiscent of Sixties posters. And the figurative works of Wilhelm Sasnal veer from a close-up of a futuristic car's exhaust pipes to two Polish workers in a bleak factory.  The large central exhibition space is given over to Albert Oehlen whose huge canvases range from some Sidney Nolanish bleached bones to organically roiling abstracts. And lastly there's Thomas Scheibitz's muted, architecturally influenced pictures of bleak tower blocks and houses (he's one of Germany's artists at the current Venice Biennale).  Saatchi is definitely a man who knows his own mind and buys what he likes, unlike the 19th-century collectors of Boston whose collective acquisitions are at the Royal Academy's Impressionism Abroad show. A well-heeled but conservative bunch, the Bostonians took a bit of persuading to buy the outré work coming out of France at the time. A number of American artists had been there (Singer Sargent studied with Monet at Giverny, William Morris Hunt with Millet in the Barbizon) and it was they who coaxed the scions of Boston to buy Impressionists, a move as radical then as Saatchi's purchases now.  The show is a gentle mixture of French and American artists to show the effect Degas, Monet, Pissarro, Renoir et al had on the Americans, perfectly illustrated in an exquisite little beach scene by Singer Sargent you'd initially mistake for a Boudin.  By 1892, the first Monet exhibition was held in the USA and all 21 works came from Boston collections. American painting went on to be transformed from 'the school of mud', as one critic at the time described it, to 'the school of the open air'. Last December, Charles Saatchi modestly described art collectors as 'pretty insignificant in the scheme of things'. How very wrong he was.
Art: Collectors with deep pockets are a vital force when it comes to creating good art, says Caroline Boucher.