Born in Florence, he came from a family of wealthy textile traders. Magnelli taught himself to paint, studying from pictures in museums and from fifteenth century frescoes in Tuscan churches. In 1911, he came into contact with Futurism through Giovanni Papini and Soffici, and with Cubism through the illustrations in Apollinaire’s ‘Les Peintres cubists: Méditations esthétiques’, before he travelled to Paris in 1914. There, Magnelli purchased paintings by Picasso, Gris, and Carrà, and sculpture by Archipenko for his uncle’s collection. His highly organised paintings were informed by study of Piero della Francesca and Paolo Uccello, as well as by Cubism, while he also adopted the unmodulated colours and dark outlines of Matisse.
At the outbreak of the First World War, Magnelli was in Italy, where for two years he painted entirely abstract works, before returning to figuration after an interruption due to military service and illness. After the war, he painted pictures of quiet Tuscan landscapes, and figure studies in a style akin to that promoted in ‘Valori Plastici’, which owed something to Pittura Metafisica. The colour was more subdued than in his previous work. From 1925, Magnelli began to use brighter tones again, and simplified both his modelling and perspective. A crisis in confidence and uncertainty as to his artistic direction led him briefly to abandon painting at the end of the 1920s. However, a visit to the marble quarries in Carrara in 1931, and Magnelli’s decision to leave provincial Tuscany for Paris, gave his art a fresh start. His paintings of ‘Pierres’, heavily outlined large floating rocks set in an indeterminate space, bore a resemblance both to the work of Magritte and of other Surrealists, as well as to his friend Léger’s contemporary depiction of isolated objects. Prampolini encouraged Magnelli to return to abstraction, and both artists were prominent in the Abstraction – Création group.
Magnelli spent the Second World War in Grasse in Provence, where he worked with the Arps and with Sonia Delaunay. Together, they produced a collaborative album of 10 lithographs. However, this was not published until 1950, for the Gestapo arrested his intended printer, and the few proofs that he had pulled were destroyed. During this period, due to a scarcity of painting materials, Magnelli made collages and painted in gouache on gridded slate slabs. Magnelli returned to Paris in 1944, where his work provided the inspiration for many younger French and Italian abstract artists. For the rest of his career, his paintings were notable for clearly delineated hard edged forms set against large matt areas of colour. Magnelli’s example was particularly important for the development of abstraction in Rome in the 1950s among the artists of the Art Club.
Magnelli made his first two etchings at Forte dei Marmi in the summer of 1934, when he was working on his ‘Pierres’. His earliest relief prints, one of which was commissioned by Gualtieri di San Lazzaro for ‘XXe Siècle’, were made from masonite matrices in 1938. These were followed in 1941 by four woodcuts, the first of which was for the catalogue of his one-man show at the Galerie Drouin in Paris. After his collaborative lithographs of 1941 – 43 with the Arps and Sonia Delaunay, Magnelli made no more prints until 1949, when an aquatint printed in Paris by Lacourière was published by Iliazd in ‘Poèsie de mots inconnus’. He began making lithographs with Edmond and Jacques Desjobert in Paris in 1950. Magnelli contributed to ‘Maîtres de l’Art Abstrait’, one of the first major albums of screenprints to be produced in France, which was printed by Wilfredo Arcay in Meudon, and published in 1953 by Architecture d’Aujourd’hui in Boulogne -sur- Seine. He made his first linocut in 1965, which was printed in Vallauris by Hidalgo Arnéra, who became his regular printer for linocuts, including the two for Aldo Palazzeschi’s ‘La Passeggiata’, published in 1970 by M’Arte in Milan. Magnelli had accompanied the Futurist poet to Paris in 1914. In his last major print project, Magnelli made 10 lithographs in 1969 -70 for ‘I Collagi di Magnelli’, which were printed by Francesco Cioppi, and published in 1971 by Il Collezionista d’arte contemporanea in Rome. The vast majority of Magnelli’s 100 prints were made in the last twenty two years of his life. Among the other publishers with whom he worked were L’Oeuvre Gravé in Zurich, Il Bisonte in Florence, and Erker Presse in Sankt Gallen.