HARRIET K. STRATIS A Technical Investigation of Odilon Redon's Pastels and Noirs INTRODUCTION Research on the materials and techniques used by Odilon Redon (1840-1916) to create his works of art on paper was carried out over a four-year period. The aim was to gather information for the retrospective exhibi- tion held at the Art Institute of Chicago, the Van Gogh Museum in Amsterdam and the Royal Academy of Arts in London. This information was published in the accompanying exhibition catalogue and also informed our request for loans of works on paper. 1 In view of the fact that the majority ofRedon's works are undated, the investigation focused in part on how Redon modified his methods and materials over the course of his career in order to see whether there was a pattern in the artist's technical evolution which could provide a framework for dating many of his drawings. Equally important in terms of the retrospective was whether the artist's use of mate- rials has resulted in works which, today, are sufficiently stable to warrant responsible requests for exhibition loan. The research began with th~ study of a large body of works on paper by Redon in Chicago collections. Thirty- three black and white drawings known as his noirs and nine pastels were examined exhaustively; samples of media, paper fibers and fixative were taken from works spanning all periods of the artist's career for identifica- tion. Thereafter, over three hundred works in both public and private collections in the United States, Europe and the United Kingdom were studied in light of the findings made in Chicago. It was particularly fortu- nate to have the opportunity to examine many of these works under the same conditions as those in Chicago: that is, out of their frames and under magnification. At many institutions this proved advantageous insofar as it offered the opportunity to examine both the recto and the verso of many drawings, and permitted the testing of media for stability. These finding informed the study of works which could not be examined under such ideal circumstances. As a result of this investigation, new information has come to light regarding the artist's choice of papers, his drawing media, and the fixative he used to secure the media to the paper. Previously, undated drawings could not be unequivocally linked to specific moments in the artist's career. Now, based on changes of pattern in the artist's use of materials and techniques a clearer picture of his devel- opment has emerged. Moreover, the findings have proven that many ofRedon's works on paper are much more sta- ble than traditionally thought to be, reflecting Redon's own concerns about the potential fragilityof the media in which he worked. MEDIA AND FIXATIVE-THE NOIRS The materials used by Redon to create his noirs changed during the course of his career as he became increasingly aware of the variety of black drawing media available to him. In the earliest noirs Redon used a combination of vine and oiled charcoal with touches of compressed charcoal. He would also use black crayon, most likely conte crayon, sparingly.Fabricated black chalk, a much harder and black- er medium than the various charcoals used by the artist, was introduced in the mid-to-late 1870s, at which time he also began to use compressed charcoal more extensively. He would use these harder media primarily to outline compositional elements over broad tonal passagesof char- coal. After the mid-1880s, black pastel appears with increased frequency in the noirs, its presence signaled by a cool, blue-black tone and velvety surface quality. Redon reserved its use for the last stages of working over grayer and browner media. As a result, lines of black pastel stand out from and are accentuated by the warmer-toned media around and beneath them.2 During the course of working, Redon intermittently fixed his drawings. As the final step in completing a work, additional fixative was spray or brush applied to the verso of The Book and Paper Group Annual 14 1995