And what better place to start than with Martin Lewis - an artist I'd never heard of before, but discovered in a special exhibition at, of all places, the British Museum . The exhibition places Lewis next to Hopper, and it is a place he richly deserves. Lewis' prints have the timeless quality of black and white photographs - breathtakingly realistic in detail, they deploy a spectrum of shades to create a vision of New York that is as murky as it is translucent, that both celebrates the contemporary and transcends it to suggest something darker, more human. This is the soul of the city captured not in light, but in shadow; this is the language of noir - an alchemy by which the ephemeral is transformed into the achingly beautiful.
In Spring Night, Greenwich Village (above) for instance, Lewis captures both the hustle of the city and the plodding stillness at its heart. The street is crowded with shadowy figures - a couple kisses in a doorway, children and pedestrians hurry past. Yet even as we absorb this everyday traffic our eyes are drawn inexorably to a figure in the center who stands silhouetted against the light - a girl who stands before a lighted storefront, watching the cobbler inside as he bends over his work. The child's stationary pose, her turned back (most of the other figures are seen sideways), the light through the shop window - all these serve as a visual break in the rhythm of the print, focusing attention on the girl, making us pause and take notice even as she herself is doing. And in that moment of contemplation an everyday street scene is turned into a minor epiphany, an image of youth confronting age, of spring confronting night, a break in the daily round of existence as the mind stops to contemplate some harsh reality, or to watch, fascinated, a sight it has passed by many times but never really seen before. There is both wonder and horror here, but more than that there is a sense of being confronted with something preternaturally true that must be made sense of - an image every bit as glowing and brilliant as the window the girl stands facing, and one that casts a shadow in the mind as long as the one falling behind her.
A similar feeling of confrontation informs Passing Freight, Danbury (below) where the dynamic, invading presence of the train is counterpointed against the two umbrella-carrying figures who stand waiting for it to pass. Here again we have an external reality that the central figures in the image are forced to confront, yet it is the presence of these two women, as well as the sleepy looking house towering above them, that anchors the train in a specific landscape, gives it both meaning and a sense of proportion. Here is a meeting of shadowy vectors, a balance of force and stasis temporarily achieved, the juxtaposition of the train and the house perfectly paralleled by the lines of electricity running horizontal along the top of the painting and the pillar rising vertically to meet them. But notice also the precision with which Lewis renders the light effects here - the ray of the locomotive's headlamp radiating out into the unknown, the glint of light on the metal of the train, and the sheen of the road after the recent rainfall (remember the umbrellas) so that the sidewall of the house is reflected on the pavement.
My favorite Lewis print of all though is Saturday's Children (below) with its vision of a weary humanity. This time the confrontation is two fold - on the one hand the everyday storefronts on the left seem at odds with the turret like buildings rising on the right, their mythic quality enhanced by the sunbeams that come streaming through them, bathing the scene in light. But there is a second confrontation here, one between the viewer and the approaching crowd. One woman, in particular, stands out - she is two steps ahead of the others, alone, facing straight at us, and almost vertically above her rises a lamppost shaped like a weighing scale - so that this unremarkable figure, this face in a crowd, is transformed into a kind of nemesis, and we are forced to confront, in the semblance of an ordinary passerby, the faceless drudgery of work, the monotony of existence, and the endless stream of days that approach us and go by unnoticed, unremarked.
The exhibition has many other delights to offer. There's Hopper of course - with the haunting Night on the El Train and the starkly scintillating Evening Wind. There's Bellows with his Stag at Sharkey's in all its sweaty, muscular glory and Business Men's Bath where the clean, proud lines of youth jostle side by side with the bloated self-importance of middle-age. There's Thomas Hart Benton's The Race, where a horse's streaming mane is echoed both in the pure curve of its reflection in the water as well as the spume of smoke the racing train leaves behind it. There's John Marin's delightful Brooklyn Bridge Swaying where a few deft pencil strokes transform the solidest of structures into a jazz like visual improvisation that you can almost see swinging in front of you. The horrors of war find expression through Benton Spruance's Riders of the Apocalpyse (left) with its faux-cubist image of planes flying through the searchlight torn sky, and Tranquility (right) which shows the painter at work wearing a gas mask while air raids carry on outside. And just in case you were getting sick of all this black and white there's always the apocalyptic Europa (below). All in all, an exhibition definitely worth the visit.
 What an exhibition of Twentieth Century American Prints was doing in the British Museum I don't know. Any more than I know why the gallery showing the exhibition also included a 'cartoon' by Michelangelo.