Sonnier first introduced fluorescent light tubes into his work in 1968 and made it his primary medium for the next two years. The first playful works were followed by the 'Ba-O-Ba' series, a more orderly body of work begun in 1969 and continued through to 1977 when Sonnier began the 'Sel' series. The 'Ba-O-Ba' series is characterised by the use of glass sheets in simple geometric shapes - circles, squares and rectangles - combined with straight lines of fluorescent tubing. Sonnier also allowed the looping black electrical cable connecting the tubing to the transformer to participate in the composition.
The title of the series 'Ba-O-Ba', according to Klaus Kertess, puns on the word for light bath in Haitian French,1 referring to the subtle atmospheric effects when these fluorescent works bathe their surroundings in light. Curiously, the coloured light becomes almost tangible and the walls and floors supporting the structure appear less substantial. The glass sheet, with its ability to transmit and reflect light, also serves to maintain this ambiguous materiality. Sonnier stated that the 'Ba-O-Ba' pieces are also about the viewer's image being reflected in the piece: 'Some pieces actually used mirror rather than clear glass as in your [the Australian National Gallery's] work'.2 Untitled 1969 is one of the earliest of the 'Ba-O-Ba'pieces and its two circular glass pieces differ from the more usual rectangular sheets in the series.
According to the artist the 'Ba-O-Ba' series has several groups made in different countries. One is from Germany, one is from Belgium and one is from France, as well as the group made in the United States. 'There are approximately ten pieces per group, although some exist in drawing only and have not been built yet.'1 Untitled 1969 was made in Germany for exhibition at Galerie Rolf Ricke, Cologne.
Michael Lloyd & Michael Desmond European and American Paintings and Sculptures 1870-1970 in the Australian National Gallery 1992 p.396.