perceptive dynamic, to her subsequent Volumi a moduli sfasati (volumes made up of out-of-phase parts), in which she used a hole punch to make rhythmic sequences of holes in layers of rhodoid (a transparent plastic material), superimposing them to generate interferences. Despite the obvious differences, it is these latter works, in their investigation of transparency and their dematerialisation of the surface image, that exhibit a parallelism of ideas with Verheyen’s creative experimentation of that period, though his focus on a direct relationship between light and colour excludes any rhythmic/temporal dimension from the immaterial. Reflection on transparency was also central to Manzoni’s investigations in the early 1960s. In a letter he wrote to Verheyen from Albisola on 1 August 1961, he says that he has begun “to think of the text on the immaterial”, as well as producing some “new works, even hairier than the previous ones I showed you in Milan: made using fibres 15-20 centimetres long” and “two new linee (lines): one 1000 metres in length, the other 1140”. The first of these developments indicates an increased use of synthetic materials and the second, a persistent conceptualising intention in making the drawn line disappear into sealed containers, larger in size than the first linee created in 1959. Also from the early 1960s dates the first draft of the book Piero Manzoni: The Life and the Works, planned as a publication consisting of nothing but transparent pages, and advertised by the Petersen Press in 1962, shortly before Manzoni’s untimely death in February 1963. In the autumn of the same year, Fontana, Verheyen and Hermann Goepfert completed a joint work interpreting the same dimension of immaterial totality, in this case by including a further component: sound.28 Transparency as a rhythmic dematerialising element appears again in the project for an environmental sculpture conceived by Fontana and built under Verheyen’s supervision for the “Integratie 64” exhibition, held in Deurne (Antwerp) in October 1964. This is how Fontana presented the plan to his friend in a letter from Milan, dated 15 June 1964: 28 The work was based on Goepfert’s idea of the Optophonium, in which lights pulsate in time with an electronic sound impulse, producing a synthesis of light and sound.
I am enclosing photographs of a sculpture project for the “Integratie 64” exhibition. If the project interests you, I can make a larger maquette in sheet metal and you can reproduce it on an even larger scale, 4 metres or more, 5 or 6 metres, in stainless steel. The sculpture has holes and reliefs and must be lit from inside
monography of the works of Jef Verheyen