When Time as Matter was presented at MACBA in May 2009 it took up the Museum's exhibition spaces in their entirety: the three floors of the Meyer building, the Capella MACBA and the MACBA Study Center. The exhibition assembled a total of 320 works, which presented the Museum's most recent acquisitions and highlighted the new lines of research that had been guiding it since 2008.

The works on the ground floor offered a representative and relatively autonomous overview of the themes of the exhibition, and they remained on display once the larger Time as Matter project had come to an end. This smaller showcase began with documentation on the exhibition Contemporary American Painting in the Collections of the New York MoMA – which had been held at Barcelona's Palau de la Virreina in 1955 – before moving on to the art of the "second"avant-gardes. It showed how the artistic movements of the second half of the twentieth century emerged one after the other and coexisted in a scene bristling with influences, interferences and parallelisms.

The exhibition included works by Lothar Baumgarten, Jean-Marc Bustamente, Eduardo Chillida, Constant, Öyvind Fahlström, Gego, Joan Hernández Pijuan, Craigie Horsfield, Manolo Laguillo, Morris Louis, Gordon Matta-Clark, Robert Motherwell, Jorge Oteiza, Pablo Palazuelo, Joan Rabascall, Albert Ràfols-Casamada, Robert Smithson, Clyfford Still, Antoni Tàpies and Lawrence Weiner, entre d'altres, among others.

The exhibition Time as Matter will occupy three floors in the museum from May 15 to August 31, though the works on Floor 0 will be on public view from May until the end of 2009.

Time as Matter opens with documentation relating to the presentation in Barcelona of the show "Contemporary American Painting in the Collections of the MOMA of New York", which took place in 1955 at the Palau de la Virreina and the Palau d'Art Modern (later the Museum of Modern Art, housed in the building now occupied by the Catalan Parliament) as part of the Second Hispano-American Art Biennial. The exhibition formed part of the diplomatic and cultural exchanges between the United States and Francoist Spain, which was discovering abstract art and the useful role it could play in foreign policy. The inclusion of works by the leading American Expressionist artists helped to consolidate Catalan Pictorial Informalism, enabling it to catch up with international abstract movements. Contemporary American Painting… featured works by Clifford Still, Morris Louis, Robert Motherwell, Ad Reinhard, Philip Guston and Franz Kline, alongside pieces by such Informalists as Joan Hernández Pijuan and Modest Cuixart and material works by Antoni Tàpies. Saura and Millares were compared to Kline and Motherwell with their powerful brushstrokes, whilst sculptures by Jorge Oteiza and Eduardo Chillida completed this exploration of recent abstract art.

At the same time, in Europe, other artists were embarking on very different research. In 1956, the Dutch artist Constant began working on the project New Babylon, the latest global expression of utopian thought. Along with members of the Lettrist International and, later, the Situationist International, led by Guy Debord, the artist launched a new revolution against consumerism, modern town planning and the impoverishment of everyday life. Reviving the early Constructivists' interest in experimentation, Constant worked with new materials but, above all, developed an ideological project to propose a new way of living, a new way of relating. New Babylon is not a new project for a city because its construction would be in the hands of its residents, not architects. In stark contrast to the functional planning of modernism, its basic premises would be to generate play and disinterested pleasure. This critique of functionalism, combined with the conviction that play is an essential component of life, would re-emerge later in the European Pop Art movement.

Constant continued to work on New Babylon until 1972, when Hans Haacke presented Shapolsky et al. Manhattan Real Estate Holdings, A Real-Time Social System, as of May 1 (1971), denouncing the way in which the city has become the scene for speculation and profiteering. In City-Slivers (1971-1976), Matta Clark also provides a clear and bitter example of the transformation the city has suffered since the spirit of liberation blew through in the 1960s and 70s. Clark shows it to have been transformed into a productive machine.

At the same time, a new generation of artists was escaping from the urban environment to propose the landscape as the support for their work. Robert Smithson theorised about the distance between site and non-site with reference, precisely, to the concretion of nature and the abstract quality of the exhibition space (gallery, white cube...). His film Spiral Jetty (1970) features one of Smithson's most important works in this respect, one that rejects the architectural space. Spiral Jetty speaks of another time that the work is capable of constructing, of another relation between linear history and the constant transformation of energy that the universe requires.

Outside both the conventional exhibition space and the city, nature provided unusual materials and dimensions. Lawrence Weiner made a crucial contribution to art when, in 1968, he declared that: "...the piece need not be built...", conferring an essential role on the receiver of the work by giving them the option of deciding "the occasion of receivership". Weiner soon realised that he could replace the action itself by formulating it in language, allowing the receiver to execute it as they pleased.

The clash between nature and culture is a key theme in the work of Lothar Baumgarten from the late-60s on. In his series Montaigne (The Great Savannah), Venezuela (1977-1985), Baumgarten critiques the supposed realism of photography by inserting colours and words into his passe-partouts, indicating everything that photography can never transmit—tastes, smells, temperatures, etc. The mural Salto (Pipa Cornuta) (1977) features a waterfall formed by the names of the rivers in the region in their original language, place names being the last refuge of these languages, which are fast becoming extinct.

In the 1970s, in a setting closer to home, a new, contained rationalism emerged. Outstanding examples of this tendency, which made extensive use of calculus and mathematics, can be found amongst the works of Pablo Palazuelo and, later on, the likes of Soledad Sevilla, Pic Adrian and Chancho, in which expression takes second place to line and pure geometry. However, in Venezuela, Gego imbued these elements with a more organic, incorporeal sensitivity.

In contrast to this section, the exhibition also takes a look at European Pop Art and the revival of the desire for reality. Inheriting the New Babylon spirit, Pop Art produced in Europe pour criticism on consumer society and media manipulation. Richard Hamilton is one of the key figures in the moment. Hamilton's fascination with Marcel Duchamp led him to spend long periods in Cadaqués after his first stay there in 1963. The British artist is an essential figure in the development of the Galeria Cadaqués, the tiny gallery that was a bastion of avant-garde art in the 1960s and 70s. It was here that the presence of Duchamp, Dalí, Cage, etc., connected Catalan art to the avant-gardes from the earlier part of the century. The works that the gallery's mainstay, Lanfranco Bombelli, has donated to the museum include such outstanding pieces as the Collaborations of Ch Rotham, produced by Richard Hamilton and Dieter Roth in 1976.

Hamilton and other Pop artists also played a decisive role in the development of several Catalan artists, such as Joan Rabascall, Jaume Xifra, Benet Rossell and Miralda. Some went to London, where they frequented Hamilton and Lawrence Alloway, later meeting up in Paris to create collaborative works—Ceremonials, for instance—parallel to their individual development. In the context of European Pop Art, which did not celebrate the industrialisation of consumer goods and objects, but denounced the impoverishment it caused, we find the work of Pere Noguera, whose use of photocopy techniques shows how the product can become simulation, the shadow of itself.

Floor 0 ends with a work by Reimundo Patiño, O home que falaba vegliota, a satirical story in the form of a comic strip, metaphorically depicting the situation of the Galician language. Even the Pope and the Pentagon persecute the last Vegliota speaker, who ends up in the hands of the murderous Gran Asesino Mundial Pepiño Manteiga.