The English painter Francis Bacon seems to be the great exception. The new paintings he is showing at the Marlborough-Gerson Gallery are virtuoso performances of a kind that are rare even in an age of extraordinary technique. He is one of those painters who appears to achieve exactly what he sets out to achieve. Clearly he has a lot more on his mind than exercises in technical excellence, however. He is a connoisseur of extreme emotions, with a taste for the macabre and a gift for transmuting the psychopathology of everyday life into a compelling and very personal pictorial imagery. One's interest in Mr. Bacon's painting shifts straightaway from the particularity of the subject to the distortions the artist indulges in the rendering. His depiction of male nudes may aspire to a condition of existential candor, but it concludes in a kind of perverse parody of Rubensesque hedonism.