These artists’ radical reduction of the palette—which extended beyond paintings to encompass reliefs and sculptures—highlighted art’s potential to move beyond its longstanding role of representing the visible world and of reflecting the subjectivity of the artist.

Yves Klein’s Monochromes proved especially influential for artists in the ZERO network. He applied a dense expanse of pigment across the surface and around the edges of his unframed pictures. This approach resulted in works that emphasize pure color and appear almost to be objects floating off the wall. At the same time, Klein’s monochromes allude to abstract ideas and metaphysical concepts, such as the immaterial, space, and the void. The older but no-less-influential Italian artist Lucio Fontana opened up new horizons with his Concetti spaziali (1947–68), a series that includes single-color paintings with slashes that direct attention to the space beyond the picture plane. Otto Piene used stencils to lay paint on canvas in grid-like patterns intended to call attention to the play of light. In a related approach, Brazilian artist Almir Mavignier created works with patterns of colored paint droplets with pointed tips that emphasize light and shadow and have a discernible physical impact on the retina. Heinz Mack applied serial lines to his monochrome paintings and reliefs to generate a sensation of dynamism that makes the surface seem to vibrate. Günther Uecker enlivened the surface of his monochromes with utilitarian materials like corks and nails, while Enrico Castellani used nails to create pictures that initially look like flat, single-color paintings, yet upon closer examination reveal themselves to be dimensional reliefs. Other members of the ZERO network also turned to everyday materials ranging from cotton threads to roof tiles. In his Achromes (1957–63), Piero Manzoni tested the limits of the medium by employing unusual, colorless materials like bread and Styrofoam, and herman de vries added sand to white paint in a series of sculptures that reflect his desire to create “homogeneous structures.”

Rather than destruction, fire stood for the creation of innovative artistic vocabularies. In their desire to distance themselves from the gestural abstraction of European postwar Tachisme and Art Informel, these artists used the chemical process of combustion to introduce an element of chance in their work. Yves Klein and Otto Piene were the most prolific, both creating entire series of fire paintings. Klein used a flamethrower to char the surface of laminated fiberboard, sometimes combined with a technique he used in his Anthropometries (Anthropométries), in which he instructed a female nude model to act as a “living brush” and use her body to apply a thin layer of water to the board. Once burned, the water generated ghostlike figures. Piene mostly used candles to burn the surfaces of his canvases, resulting in deep-black, light-absorbing, circular forms made of soot that reveal subtle variations on their black surfaces. For other ZERO artists, the use of fire was more accidental. Piero Manzoni and Jef Verheyen created a series of works on paper using fire during an evening they spent together at a bar. Henk Peeters charred plastic membranes, which melted rather than burned, adding a material, relief element to his work. Of all the artists, Bernard Aubertin was probably the most interested in fire itself, more so even than in its result. Aubertin created objects covered in aluminum that he perforated with hundreds of holes in which he placed matches. In front of an audience, he would set the matches on fire, creating an ephemeral performative action that only existed for as long as the artwork would burn.

The publication’s mesmerizing frontispiece, with nine irregular columns repeating the word vibration, illustrates the concept and speaks to much of the art of the emerging ZERO generation.

Pol Bury, Jesús Rafael Soto, and Jean Tinguely had debuted their interrogations of real and virtual movement in Paris in the mid-1950s. Their pioneering work paved the way for subsequent experiments by other ZERO artists. For Bury and Tinguely, electric motors offered a means of activating elements affixed to support surfaces, frequently wooden boards. Tinguely’s work in particular would inspire a number of other ZERO artists to begin making kinetic art. However, many continued to explore the potential of paintings and reliefs to convey a sensation of motion. Soto placed thin metal wires in front of painted black-and-white lines, the two elements combining in the eye of the viewer to form a dynamic surface that almost seems to quiver and conveys a sense of instability, metamorphosis, or transformation. In his Dynamic Structure (Dynamische Struktur) paintings, Mack alternated light and dark lines in such a way that the surface appears to vibrate. Similarly, Almir Mavignier explored contrasts through both color and composition, using, for example, a combination of convex and concave patterns in black and white to generate the optical illusion of vibration. Like Mack, who, beginning in the late 1950s, worked regularly with metal because of its luminous qualities, Günther Uecker recognized metal’s viability for creating the impression of vibration. He covered panels and objects with fields of nails, sometimes incorporating an artificial light source to bring out their luminous quality. Still other artists found industrially produced materials to be successful vehicles for exploring dynamism in art. Gianni Colombo worked with Styrofoam blocks, Walter Leblanc polyvinyl strips, Adolf Luther and Christian Megert mirrors, Uli Pohl acrylic glass, and Nanda Vigo sheets of corrugated glass.

Some focused on its fundamental role in enabling sight, some explored its more conceptual or philosophical implications, such as its opposition to darkness, and still others used light itself—fire and electric bulbs—as a material for making art. The widespread interest in light in part derived from the recent experience of World War II, when aerial campaigns lit up the night sky in various countries in Western Europe, and civilians were told to keep their lights off in order not to draw attention to populated areas. As many of these artists have noted, with the end of the war, the lights came back on, both literally and figuratively.

By the late 1950s, Otto Piene had devised a method of painting with hand-punched stencils that enabled him to produce areas of paint in relief that create a play of light across the surface of the canvas. In 1959, he used one of these stencils and a handheld lamp to project light patterns in a darkened room, creating the first of his series of Light Ballets (Lichtballette, 1959–2014). A year later, Piene began making mechanized, perforated light machines in various formats and materials, resulting in a defining body of work that he presented in dedicated galleries and choreographed with timers. In parallel, Heinz Mack started using metal as one of his primary materials, chosen for its ability to make the movement of light visible and to illustrate the concept of vibration. Hermann Goepfert also used metal elements to reflect the lights on his performative relief Optophonium (1961–62), which unites the visual with the acoustic, manifest as an accompanying tonal score. Adolf Luther and Christian Megert both used mirrors, resulting in surfaces that made visible the ever-changing effects of light and brought the space of the real world and the viewer into the work of art.

Many of these artists were included in exhibitions of the period titled after or organized by the themes of light and movement. One of the most important presentations was at Documenta 3 in Kassel, Germany, in 1964, when Mack, Piene, and Günther Uecker presented Light Room (Homage to Fontana) (Lichtraum [Hommage à Fontana]), a room-scale installation comprised of seven kinetic sculptures and a slide projection of one of Lucio Fontana’s paintings. Timers determined the choreography of the motorized sculptures, many of which either incorporated light or were illuminated by an electric light source. The space thus underwent constant alterations and enabled the viewer to experience the abstract concepts of time and transformation.

In particular, artists associated with Paris-based Nouveau Réalisme valorized the use of these materials. While previous art movements, such as Dada, had also resorted to everyday materials, the context of the economic boom in which this renewed interest emerged was very different. Not only did everyday materials carry a symbolic or emotional value, they also represented a new daily experience in a postwar society of mass production and consumption. The use of everyday materials also resulted from the artists’ attempt to blur the boundaries between art and life by introducing recognizable materials in their artistic production, moving away from the more traditional practices of painting and sculpture.

To create his Trap Pictures (Tableaux pièges), Daniel Spoerri would glue to the table all the objects that were left behind at the end of a dinner with friends. For the 1962 tentoonstelling nul exhibition at the Stedelijk Museum in Amsterdam, the Dutch artist Jan Henderikse created an entire wall made of beer crates, including the bottles, which he sourced from a local brewery. For his 1957–63 series Achromes (literally, “absence of color”), the Milan-based artist Piero Manzoni used unconventional materials like bread rolls, which he covered in kaolin and white paint. Hans Salentin made reliefs with roof tiles, and Henk Peeters created kinetic sculptures with the feathers from bed pillows. Günther Uecker’s oeuvre probably represents one of the most consequent attempts at exclusively using a singular everyday material, in his case the nail, which he hammered into canvases and objects. To make his kinetic sculpture New York Dancer I (1965), the artist draped a piece of cloth over steel rods and covered it in long nails with the points facing outward.

The distribution of self-edited, low-budget publications was an essential tool for the ZERO artists in their attempt to share their ideas with a wider international audience. In Germany, Heinz Mack and Otto Piene edited the magazine ZERO. The first two issues were published in 1958 at the Abendausstellungen (Evening Exhibitions), which they organized in their studios in Düsseldorf. The third and final issue appeared on July 5, 1961, launched in combination with an exhibition and street demonstration at the Galerie Schmela in Düsseldorf titled ZERO: Edition, Exposition, Demonstration. The Dutch artists Armando, Henk Peeters, and herman de vries published the first issue of nul = 0 in November 1961. A second issue, edited by Peeters and de vries, followed in 1963. The artists’ ambition was to regularly share news about art exhibitions and contemporary developments in literature. Enrico Castellani and Piero Manzoni, Milan-based artists, edited the two issues of the magazine Azimuth in 1959 and 1960, which combined critical texts and art images, including reproductions of artworks by international contemporary artists.

Illustrated catalogues were also printed on the occasion of exhibitions, which were organized by artists, dealers, or institutions. The catalogue accompanying the exhibition Vision in Motion–Motion in Vision in Antwerp in 1959 integrated the ZERO group’s visual language into its design by using silver foil. For tentoonstelling nul at the Stedelijk Museum, Amsterdam, in 1962, the exhibition brochure could be unfolded into a poster that reproduced the artworks of the participating artists on a grid. The number 0 was often featured on the covers of these books, exemplified by the particularly interesting exhibition catalogue design by Robert Indiana for Group ZERO at the Institute of Contemporary Art (ICA), University of Pennsylvania, Philadelphia, in 1964.