“The transformation that is taking place before our eyes in photographic methods and their effects is critical,” wrote Walter Peterhans in 1930. He had experienced that transformation firsthand when, in 1928, he was appointed to head the newly created photography workshop at the Bauhaus in Dessau–a sign of the acceptance of photography by Europe’s most influential art school.

Technology played a major role in stimulating the creative surge in photography after World War I. The development of the Leica, the first camera to use 35-millimeter film instead of much bulkier larger formats, made a high-quality yet eminently portable camera available to a wide public. “Many more people experimented with photography during that period, partly because of the new accessibility of photography due to the invention of the Leica,” says Kathleen Lamb, curator of one of two current exhibitions, at Northwestern University that showcase German photography from the 20s and 30s.

Photographers also found ready markets for their pictures as the American and European publics devoured the new picture magazines. “We’re familiar with Life magazine,” says Lamb, “but the movement in photojournalism really grew all over Europe and the United States during the period. And there were many German picture magazines, French publications, British publications, so there was a great outlet for people who were using cameras like the Leica, who could work easily outside of studios, in the street, wherever they wanted to work very quickly. And their outlet or their way of showing their work was through the publications.”

Photographers responded to the attention by experimenting with a wide variety of styles. Perhaps most were the images made without a camera, such as the photograms of Laszlo Moholy-Nagy and Elfriede Stegemeyer. Following the lead of dadaist Man Ray, these artists placed hands, leaves, or pieces of cloth on light-sensitive paper to create simple and often abstract patterns in black, white, and perhaps a few distinct shades of gray. “The effect,” wrote Moholy-Nagy, who taught at the, Bauhaus from 1923 on, “is sublime, radiant, almost dematerialized. In this way the potential of working with light is far more completely exploited than had previously been the case in painting.”

Many photographers of the day were haunted by accusations that photography was merely a pale imitation of painting. In the exhibition, solarized prints by Andreas Feininger and Konrad Cramer testify to an attempt to create an entirely new visual languange for photography. Others bowed to the influence of the cubists and dadaists and began making photo collages; an untitled example by Franz Ehrlicher features miscellaneous images and words selected and assembled purely for the sake of design.

This practice of experimenting with materials meshed well with Bauhaus philosophy. Among the most attractive items in the show are a pair of still lifes by Peterhans–almost two-dimensional, they depict assemblages of simple materials such as wire, bits of fabric, a thin lemon slice, all arrayed on wood. They celebrate not only the texture of the objects, but also the texture of the paper they’re printed on.

Other photographers, however, were concerned with exploring the world in a broader sense. Erich Salomon busied himself snapping photos of major political events, such as the Second Hague Conference on Reparations in 1930. Albert Renger-Patzsch is represented in the show by a lyrical landscape of oak trees and fields in snow. The most memorable landscape, though, is August Sander’s 1936 view of a highway bridge on the new Reichsautobahn. The stark, broad roadway pierces an empty landscape, devoid of any other signs of man. It is an eerie image, reflecting the dehumanization then going on under the Nazi regime; this monumental construction indeed looks like it could last a thousand years, as the Reich was supposed to do.

A certain ambivalence toward technology informs a number of the photos. In Werner Mantz’s untitled view from 1937 or ’38, a factory wall and a row of chimneys dwarf a passerby on a bicycle. Herbert List’s photo of a steamer’s superstructure, on the other hand, is simply a document of a well-built piece of machinery.

The students and teachers at the Bauhaus had primarily positive reactions to technology. “To be a user of machines is to be of the spirit of this century,” wrote Moholy-Nagy, the institute’s greatest believer in the marriage of art and engineering. Several studies in the exhibition show playful attitudes to new technology: a striking image by Walter Funkat depicts preparations for a festival at the Bauhaus, reflected in one of hundreds of metallic spheres suspended from the ceiling. The students with cameras at the center of the photo look perfectly content in their high-tech surroundings.

Josef Albers, the subject of the other exhibition at Northwestern, used photography not to comment on technology, but to continue the explorations in geometry that he had pursued in his painting, stained glass, and furniture. The Bauhaus student and teacher is best known for his “Homage to the Square” paintings, a series of paintings of squares in varying colors and proportions that occupied him for 20 years while he taught in the U.S. after World War II. Some of his photos illustrate his interest in basic geometric forms: a photo of swallows on telephone cables is as ordered as a De Stijl painting; seams on a tent become an abstract array of dark lines.

This show, put together by the Josef Albers Foundation, includes many images never exhibited before. Most are mounted in pairs or larger groups: Albers contrasts shots of trees and their shadows, ripples in shallow water or railroad tracks from different angles, a lake under both cloudy and sunny skies. Laundry hangs still on a line in one photo, and blows in the wind in another in absurd mimicry of its usual human occupants.

Perhaps the most satisfying pictures in the show are Albers’s portraits of his contemporaries. Snapshots of his associates, mounted in series of up to a dozen, show a more human side of the great artistic achievements of the 20s. There is Kandinsky, smoking a cigarette and looking professorial in a tweed jacket; El Lissitzky, beaming in ten consecutive photos; and a grim Paul Klee, looking for all the world like a stodgy burgher, not like the creator of intricate, cartoonish fantasy worlds.

“German Photographs of the ’20s and ’30s From Chicago Collections” and “The Photographs of Josef Albers: A Selection From the Collection of the Josef Albers Foundation” can be seen today through August 9 at the Mary and Leigh Block Gallery on the south end of Northwestern’s lakefront campus, 1967 Sheridan Road in Evanston. The gallery is open 10:30 to 4:30 Tuesday through Saturday, noon to 5 Sunday, and for one hour in the evening before events at Pick-Staiger Concert Hall and the Ethel M. Barber and Josephine Louis theaters. Admission is free; more info at 491-4000.