I'm Amazed – the graphic art of Ed Ruscha, Bernard Jacobson Gallery, London

Where does Ed Ruscha fit in to the post-war US art scene? Some, aligning him with Warhol, have claimed him for pop art.

Others, spotting the influence of Magritte, have called him a bit of a surrealist, a dadaist or even an early conceptual artist. The fact is that he is a bit of all these things and none of them, not really. He is too fresh and too odd to be kidnapped by others.

This spasmodic survey of his graphic art covers about twenty years, from the late 1960s to the early 1990s. We see again here many of the images we have seen as paintings – HOLLYWOOD, writ high in letters along the line of the hills; the Standard gas station, whose clean lines stretch away to infinity.

Yes, Ruscha is fond of re-working his images in different ways, squeezing them out for what else they might yield. Prints can distil images; they can boil them down to more essential versions of themselves. His paintings, generally being on a much larger scale, are more plangent and engulfing.

This show is for the most part about playing with words, about exploring how words work on us as images. Sometimes these words are relatively free of information content, they seem to float free of their meanings; at other times, what they mean feeds into how Ruscha has chosen to present them to us visually. What we discover is that it would be just as easy to pigeon-hole Ruscha as a concrete poet as to align him with movements in art. Ruscha's visual trickery - and that's exactly how it often feels – often makes us laugh.

Take a wonderful piece here called 'Lisp'. The letters of the word itself are constructed out of droplets of water that, by some miracle, have flowed together to form this odd locution. It is quite hard to read but, once read, there is no denying that's what it is.

What amuses us the fact that the word lisp seems to have other words pressing up against it, waiting to be admitted precisely because he has used the 'idiom' of water, and because lisp seems to be a near anagram of some of these words. These words are lips (moist perhaps), drips, spills. Only lisp is not quite as aqueous as the others (and lisping, you have to agree, may or may not involve some moisture content....)

I'm Amazed – the graphic art of Ed Ruscha, Bernard Jacobson Gallery, London W1 10 Jan-15 Feb