The Núcleos (Nuclei) series embodies Oiticica’s concept of nuclear colour: colour that ascends or descends in gradual hues from its centre. These ‘chromatic environments’ consist of multiple hanging panels, painted on both sides, and arranged at 90-degree angles to form a maze. The openings between the panels are as important as the panels themselves, recalling the play of negative and positive spaces in the earlier Metaesquemas series. The viewer’s perception of the works shifts with changes to the light and movement of the surrounding air.
Oiticica devised three types of Nuclei that he classified in terms of their relative size. The first to be made was the NC1 Pequeno Núcleo no. 01 (Small Nucleus No. 01). This includes a mirror that enhances the light and colours of the spatial arrangement, as well as allowing viewers to see themselves as active participants in the work.
Three medium nuclei (NC3, NC4, NC6) were eventually combined into a large-scale hanging environment known as the Grande Núcleo (Grand Nucleus) 1960–6. This spectacular work, with panels in tones of violet at the nuclear centre unfolding into a range of luminous yellows, amplified the spatial and temporal aspects of the Spatial Reliefs. The participation of the viewer in experiencing the colour, the effect of light and the tension between actual and suggested space in this work, is more essential than ever.