PART OF THE POWER of fresco as a medium lies in its fusion of two distinct temporalities: the time of the artist—the rhythm of his workday as he moves across the wall—and the longue durée of the artwork after it has dried into architectural permanence. In the construction of a traditional fresco, wet plaster is laid down, pigments are applied, and, as the wall dries, a chemical reaction inseparably binds plaster and pigments so that the picture becomes part of the wall, not merely a thing upon it. Ironically, producing this singularly durable art form requires a race against the clock: since the plaster can be painted only while it's damp, muralists typically apply as much plaster as they can paint in a day, then hurry to complete that section of a fresco before it hardens into history. One can often calculate the number of sessions it took to paint a fresco by looking at the areas where two separate lengths of plaster have been joined; a length is known as a giornata, or "day's work."
Perhaps on some level the Mexican muralists (the major modern artists to use fresco) were attracted by how the medium itself can serve as a metaphor for historical process, for the integration of individual labor—a long string of giornate—into the collective, the intergenerational. There is a compelling, constitutive tension between the dialectic that fresco is and the dialectical history that painters like Diego Rivera often used it to depict, a kind of populist medium specificity.
I find no such tension, however, no dance of durations, internal to the "portable murals" Rivera constructed for an exhibition that ran from Dec. 23, 1931, to Jan. 27, 1932, at the Museum of Modern Art in New York—the museum's second show dedicated to a single artist. (Matisse was the subject of the first.) Five of Rivera's eight murals are currently on view at MoMA, reassembled for the first time in 80 years from the museum's and other public and private collections. In order to solve the problem of how to present an artist best known for his large-scale, immovable works, in 1931 MoMA provided Rivera with studio space within the museum, where he produced freestanding frescoes built on rigidly braced steel frames into which cement had been poured to form wall-like supports. The first five murals, completed in time for the opening, portray Mexican historical and revolutionary subjects. With the exception of The Uprising, which depicts protesting workers clashing with soldiers, they are all in fact details—or near-details—of Rivera's Mexican mural cycles.
After the show opened, Rivera added three more panels addressing Depression-era New York: laborers operating a pneumatic drill (the whereabouts of Pneumatic Drilling are now unknown); Electric Power, in which three laborers are seen through the cross section of a riverside power plant; and Frozen Assets, which seeks to depict the stratification of urban American life. Powerful skyscrapers loom at the top of the last composition; beneath them commuters are crammed into an elevated train. In the middle we see into a glass and steel shelter where rows of the homeless and unemployed are sleeping under the surveillance of a guard. At the bottom of the panel we find an underground bank vault in which a wealthy woman admires a gold necklace. In the room outside the vault three figures—one of whom resembles John D. Rockefeller, Jr.—await their turn to inspect their deposits.
As much reproductions as new works, the Mexico-themed frescoes are free (or doomed) to circulate like photographs of the originals. In an insightful catalogue essay, curator Leah Dickerman suggests that the artist was influenced by the widely viewed photos of his own work in architectural settings and used the metal frames of the portable frescoes to imply photographic cropping. She also contends that Rivera's arrangement of these details from various murals into a new syntax in the museum space owes something to the theory of montage developed by Rivera's friend Sergei Eisenstein; instead of a linear narrative embedded in a building, we now have quick jump cuts across scenes. This is an inspired curatorial strategy for recuperating the portable murals into a narrative of leftist experiment, and might well have been in Rivera's mind, but I can't reconcile it with the work: it's hard to think of these panels as forming enough of a sequence in the first place for transitions between them to be experienced as cuts. Our desire to integrate the frescoes into some horizontal relation is more notable than any particular strategy for doing so; it indicates how the medium of fresco feels unmotivated when rendered isolate, portable, no longer indistinguishable from the wall. We want these to be something other, something more, than really heavy paintings.