Gerhard's off the Richter scale To confirm the point, Art Market Research, which has for long been producing art indices for companies such as insurance company Hiscox and The Financial Times using a slightly different methodology, has constructed a similar graph on Richter prices. In the four years since 2007 when the marked has peaked, adjusted sharply downwards and then recovered more or less, Richter prices at auction have increased by 319 percent, compared to Warhol's 109 percent. In a recent poll conducted by ArtTactic, yet another market analyst, Richter is the artist collectors and investors have most confidence in for the future. As he was such a diverse artist, painting traditional still lives, blurred paintings after photographs, and a variety of abstract paintings from coloured grids and grey monochromes to exotic multi layered abstracts made with a squeegee, the question arises which of these genres are valued most by the market. Until May 2008, it was his small number of spiritual candle paintings (up to £8 million) and photo paintings (up to £7.3 million) that commanded the highest prices. But in that month, one of his large squeegee abstracts sold to Russian billionaire, Roman Abramovich for $15.2 million. Since then, these highly decorative abstracts, of which there are hundreds, have become more sought after. Last November, one sold for a record $20.8 million to Lily Safra, the billionaire widow of banker, Edmond J Safra, who set the art market alight in 2010 with the purchase of Alberto Giacometti's "Walking Man" for £65 million. She has since donated the painting the Israel Museum in Jerusalem. In the same sale, one buyer, thought to be the luxury goods Louis Vuitton Foundation, bought another abstract, last sold in 2001 for $783,000, for $18 million, and yet another, which had sold in 2005 for $1.2 million, for $14.1 million. "The bidding came from everywhere," said Tobias Meyer of Sotheby's, "from America, Europe and Asia. People love colour. And the more Richter abstracts that are available, the more people seem to want them to the point at which they have become a global status symbol. Certainly, going round the Tate's Richter show after the sales, the abstracts seemed more than ever to be imbued with a sense of wealth and luxury. Not surprisingly, most of the paintings in the London sales are abstracts. Estimates range from £150,000 to £200,000 pounds for a 26 by 40 inch untitled work on paper in rich reds, greens and yellows, to a large oil on canvas which Christie's values at between £5 million and £7 million (pictured). The catalogue note for the latter is peppered with adjectives to describe the emerald green and azure blue palette with its palimpsests of mauve and red - "luxuriant," "regal," "majestic," "elegant" - appealing to the aspirations of would be buyers. If the market behaves as it did in New York last November, those estimates will be trumped. Richter, meanwhile, is bemused by the prices he commands. At a conference held before the opening of the Tate exhibition he said: "It's just as absurd as the banking crisis. It's impossible to understand, and it's daft.