Discussing the Terra d'ombra, Giuseppe Penone explained that he had used the 'helio-painting' technique which he had developed in part as a reaction to his interest in the etymology of the word 'colour,' which has its roots in associations with the notion of covering: 'For all that which covers, in the act of protecting, creates shade. It produces an erasure' (G. Penone, quoted in C. Grenier, Giuseppe Penone, exh. cat., 2004, p. 284). With this in mind, Penone used strips of sticky tape to take impressions of his own skin surface. Where in his Pressione works, he had projected similar 'images' against walls or paper, he now used a support that was covered with a light-reactive varnish. 'The varnish polymerises, holes form and, when you add pigment onto the varnish, it stays on the canvas in the places where the holes are,' Penone explained. 'It is not painting, it is another process.' It is instead a form of pictorial photosynthesis. Indeed, because of the nature of this process, Penone himself suggested that the technique should have been called 'shade painting,' rather than 'helio-painting' with its associations with light.
The substance that Penone added to the now-pitted surface of Terra d'ombra was umber, a form of brown earth that is used as a pigment-- for instance that Sienna (as in Burnt Sienna)-- which has the added advantage of introducing a pun to the title. Through the use of this soil-pigment, the skin of the artist was represented using, as a medium, the skin of the Earth: this creates a poetic interface between nature and man, art and the world around us. Umber is a form of soil that had associations with crafts, and therefore with man-made objects, with art and with craft, with the objects and artefacts that are the strange evidences of human existence. In Terra d'ombra, this use of a pigment loaded with reference and meaning results in a profound interface between the artist and his material that is all the more apt in creating a work that is itself the projection of the patterns of his own skin. As a final touch, Penone added bronze casts of leaves to the surface, resulting in additional shadows, and also reemphasising the connections between nature and art in his work. The leaves, cast through the lost wax technique which Penone has so long associated with natural processes, are the result of another form of transformation, another apotheosis through which the more vulnerable and perishable organic matter has been rendered in solid metal.